Step Dad Birthday Celebration

I'd been dating Amelia for almost 18 months when we were invited over for her mum's boyfriend's birthday. Amelia's parents had split up before I had got together with her and her mum was now dating a black dude called Mark. He was a tall, well-built builder who often worked nights. He'd always been nice and approachable when I met him and seemed to understand his role with regards to Amelia and her sister, Beth. He was there if they needed him but never tried to play the role of the father.

Amelia herself was gorgeous. A bubbly 21-year-old redhead with perky 32DD boobs and a large ass. She was pale, a proper English rose, with cute freckles all over. She burned easily so always made the effort to cover herself in the sun and her skin was incredibly smooth as a result.

Her sister, Beth, was seven years older than Amelia and hadn't inherited the ginger gene. She was a brunette about the same height as Amelia but carrying a little more weight. As a result, her boobs were bigger, I'd guess around 34E, and she had a much larger butt. Both girls were incredibly attractive, and it wasn't hard to see where they got it from as their mum, Jean, was the definition of a MILF. Just under fifty, her body was still tight and lean, and she rocked the same large boobs and phat ass of her daughters. As a family and as individuals they were absolutely gorgeous.

I was aware that Mark and Amelia's relationship was a little odd quite early in our relationship. Little things that made me raise an eyebrow but that I didn't put much thought into in the end. For example, he would ogle Amelia's boobs without shame when she had cleavage on show and once he playfully spanked her on the ass when she'd spoken back to him. Possibly innocent, but the spank seemed to be a little harder than necessary and he made good contact with her cheek. She didn't seem to mind though and just giggled and even her mum and sister laughed it off. He acted this way with all three of the girls, so I didn't pay much mind in the end.

On Mark's birthday we all turned up at her mum's house, me, Amelia, Beth, Beth's boyfriend Greg and, of course, Mark and Jean. It was a fun night but there was an undercurrent of sexual tensions that made me uneasy. Mark has his hand on Amelia's leg at one point as they laughed, and it was dangerously high up her thigh. Beth had gone to kiss him on the cheek when she said happy birthday and he seemed to intentionally move his face to catch her on the lips. I swear I caught him cup Jean's boob as she put his food on the table as well, but it was out of the corner of my eye.

After dinner, we were all sat in the living room, me, Amelia, Beth and Greg on the long sofa and Jean and Mark opposite on the smaller one.

"Present time!" Jean chimed happy as she topped her glass up with wine. Luckily, Amelia dealt with her side of the family's presents, so I hadn't had to put any effort in. Both girls stood up smiling and retrieved their presents from a small bag. Amelia offered hers to Mark first.

"I hope you like it," she said, twirling a long strand on ginger hair.

"You know I will," Mark replied, almost seductively. Again, I raised an eyebrow. There was such a strange atmosphere. I looked to Greg to see if he was picking up on it and was shocked to see him looking miserable, head resting on his hand. It didn't take long for Mark to tear through the wrapping.

"Oh, it looks amazing!" He said to my shock as he raised a bra and panty set. It was jet black, the bra padded and pushed up. The thong was barely there and would hide nothing. It was lacey and looked very expensive, "Thank you so much, Amelia," he said lustily and as she leaned in to kiss him on the cheek he showed no subtlety this time in pulled her lips to his and planting her with a large kiss.

"Err, wha...?" I begun as Amelia pulled away from him. Beth had already handed her present to him and Mark begun tearing it open. I looked to Greg again to see he had shrunk into the sofa now as if trying to get it to swallow him hole. I made it obvious to him that I was looking but he deliberately avoided my gaze. Even Jean was happily watching Mark unwrap.

"Lovely!" Mark announced pulling up a red set of lingerie. This one was also padded but the knickers were a French, lacey style. Beth too leant in and was rewarded with a powerful kiss on the lips.

"What's going-?" I tried before being interrupted by Jean.

"Okay, girls. Let's go and get ready!" The daughters took their lingerie and followed their mum out of the room, Amelia looking back at me with an apologetic look and mini wave before disappearing.

"What's going on?" I finally managed to say as the door closed. Mark smiled at me. I couldn't work out if it was mocking or kind.

"The girls are just sorting out my present. I suggest you just sit back and enjoy." I didn't like the sound of that. I turned to Greg again.

"What is going on?" I repeated to him instead. He just shrugged.

"It's like this every year," Mark continued as if I had spoken to him, "The girl's struggle to buy me a present so instead I give them a bit of money and my present is seeing them in the lingerie they buy." I shook my head at that, trying to process his words. My girlfriend was going to dress up in sexy underwear for him?

"Every year? What about last year?"

"Oh, right, you missed my birthday last year." Mark said, still smiling. I had to work his birthday last year. So, while I was working, Amelia was parading around in her underwear in front of her mum's boyfriend?

"It actually happened last year too?" I asked. Greg moved for the first time giving a small nod.

"I thought Amelia would have told you." Mark said.

"She didn't."

"Oh well, you might want to prepare yourself. Things will get...messy." Mark gave me a wink. I tried to protest again but the door opened, and the three girls came back in. The two daughters looked stunning. I had always had a bit of a crush on Beth even though I was dating her sister. She looked amazing in the red underwear, her boobs looking large and inviting. Amelia looked even better if possible, the blackness of the lingerie contrasting amazingly with her pale, pure skin. Her tits were almost hanging out only held in place by flimsy looking lace. The two girls turned their backs on their boyfriends to stand in front of Mark and their asses looked amazing too. Amelia's was almost completely bare look luscious. Beth's was subtlety covered with weaving lace. I almost wanted to crawl over to them and bury my face in there.

"You look great!" Mark exclaimed happily. I realised Jean had sat away from him on a chair near the door. She hadn't changed but seemed to have finished her first bottle of wine. "Shall we start?"

"Start what?" I managed to say before my question was immediately answered by both girls getting on there hands and knees. My mouth dropped open as I watched both asses slowly crawl between their mum's boyfriend's legs. Beth started to unbuckle his pants.

"Hey, wait-" I went to say.

"Shut up!" snapped Jean with venom, making me jump. Mark laughed as the girls finished undoing his pants.

"Sorry man, this is how it is. You can either enjoy the show or leave." He smiled at me again as he stopped up to help the girls pull his jeans off. His boxers were barely containing his erection. I couldn't blame him. I'd dreamt of the two girls being in the same position for me. I looked to Greg for help, but it was clear I wouldn't be getting any from him. The girls pulled down Mark's boxers and unleashed a large, dark black dick. I didn't feel like I was small, but still felt dwarfed by his size. Probably eight inches long and too thick to get a hand around. He kicked away his jeans and boxers and sat back on the sofa.

The girls hungrily buried their faces into his junk. Amelia went straight for his large black balls. She licked and sucked on them, alternating every few seconds while Beth teased the tip of his cock with her tongue. She ran her tongue up and down the sides of his shaft being taking his dick in her mouth. Mark moaned and pulled her down further onto his dick, so she gagged happily. As she slowly came back up for air, Amelia released Mark's balls and slowly licked up his shaft. Beth dropped her face into his balls and my girlfriend took his dick deep into her throat. Amelia had always been incredibly at sucking cock. I was racked with a mixture of jealousy and arousal. Mark was in the exact position I wish I could be in. Two of the hottest girls I'd ever seen, sisters no less, slobbering all over his dick. I couldn't take my eyes off the scene, although I noticed Jean had pulled up her dress on the chair and had started to softly rub herself through blue knickers. They continued to swap roles until finally, Mark pulled them off his dick which sparkled with saliva in the light.

"Who's first?" He asked, looking between the girls. Amelia's hand went up immediately.

"ME! Beth went first last time." Mark laughed and pulled her close to him by the hand. She carefully straddled his dick.

"Hang on a second," I said, very aware of my own erection as I made to stand up, "I don't really think this...I mean, I don't...it's not a..." words completely failed me as Mark moved Amelia's knickers to one side.

"I'm sorry, babe," Amelia said, looking back at me as the tip of Mark's dick pushed against her pussy, "but it IS his birthdAAAY-" her words turned into a yelp as Mark pulled her down onto his dick. I was so mesmerised that I didn't realise Jean was next to me now, carefully forcing me to sit back down.

"It's okay," she murmured over Amelia's excited squeaks, "It's just a little birthday tradition." Jean sat next to me and went back to stroking her pussy. Beth had sat next to Mark and was softly fingering herself too as she watched her younger sister work a black dick into her pussy.

To her credit, Amelia was doing very well. She took half of his dick before pulling herself up off him and burying three quarters of his cock into her. In a few bounces, she was happily taking him balls deep, her soft yelps and squeaks turning into guttural moans of delight. Mark's head was placed perfectly in between her large tits and he was kissing them all over. It didn't take long before her pussy cream started to cover his dick. Once Amelia was comfortable taking him the whole way in, Mark started to thrust upwards into her pussy, making her curse quietly with each thrust. I swear I heard her whisper, "fuck me, daddy," into his ear as she went.

I DEFINITELY heard her almost shout, "I'm fucking cumming," as she forced herself onto his big dick repeatedly. After a few more thrusts, he held her in place on his dick and she softly shook as an orgasm overtook her.

"My go," Beth said, hitting Amelia softly on the arm. With a lot of effort and shaking, Amelia pulled herself off Mark's cock and Beth took her place, Amelia's cream making it easy for her to slide down his shaft.

"Help your woman clean up." Mark said and it took me a beat to realise he was talking to me.

"Pardon?"

"Help Amelia clean up. She's going to need your support." Amelia had wriggled out of her panties and was sitting next to Mark catching her breath. At his words she spread her legs, showing her dripping wet pussy, and beckoned me over.

"Come on babe," she said with a tired smile, "It'll really help."

"The other one is such a spoilsport." Mark said and I felt Greg deflate even more if possible. "Come and play along. It's a lot more fun that way." I hesitated. Despite myself I was not angry at the situation, which was a shock. I had enjoyed watching Amelia being impaled by Mark's large black dick, but to eat her out afterwards?

But her pussy did look damn tasty.

I found myself slowly walking over to her, not entirely in control of my movements.

"Good man," Mark grunted as he thrusted into a panting Beth.

Amelia pulled me in for a kiss and whispered, "I love you", to me before forcing my head down into her soaking wet pussy. She was so wet is was unreal and she tasted different. Sweet, her cum I imagine, but also a hint of saltness that I had to tell myself definitely wasn't Mark's precum. It was a surreal situation; licking my girlfriend's freshly fucked pussy while her sister groaned and moaned on a large black cock next to us. Amelia held my held into her tightly and was happy moaning along with her sister.

After a few minutes Beth moaned that she was going to cum and Mark treated her the same way as he had my girlfriend; thrusting hard into her pussy before holding her tightly, balls deep inside her. Beth shook and moaned as she orgasmed over his dick.

"Round 2," Mark said to Amelia who immediately, almost TOO excitedly, pushed me away. She turned around and bent over the back on the sofa as Beth slide herself off of Mark's dick. I moved out of the way as Mark stood behind Amelia and had the perfect view of his huge dick penetrating my girlfriend.

"As you've been a good boy," Mark said to me as Amelia started to whimper, "You can clean Beth up too." Greg made a noise of disapproval but Mark cut his a violent glare, "You missed your chance to grow a spine." He spat at him before kindly saying, "Go on," and pushing my head towards Beth who had taken up the same position as Amelia had next to them. I crawled over to her, a little nervous as she looked down at me panting.

"It's okay," she said, smiling kindly, grabbing me by the back of the head and pulling me into her pussy. I had dreamt about going down on Beth for a long time but this was definitely not how I imagined it would happen. She tasted very similar to Amelia and I did my best to make the most of the situation, ever aware that my girlfriend was getting fucked next to me. Amelia's noises had got louder. Mark hadn't given her time to prepare this time and was relentlessly thrusting his dick into her repeatedly, grabbing her hard by the hips. Beth was pulling my head into her pussy like Amelia and was happily moaning as I licked.

My erection was now very uncomfortable and I seemed to be getting even harder at the slapping sounds of skin. After a few minutes I dared a look over to Amelia and Mark and saw him pulling her roughly by the hair as he banged her hard. I heard her whimper that she was going to cum a couple of times while I licked her sister's pussy. It felt like an hour later, but had probably only been ten minutes, when Mark hoarsely announce he was going to cum.

"Inside me. Fill me up." Amelia moaned. I tried to pull my head away from Beth but she held me close stopping me from protesting as Mark slammed himself into my girlfriend again and groaned loudly. Amelia's back was arched and she was shaking uncontrollably as Mark filled her with jizz. Finally, Beth let me go and I had a good view of Mark balls deep inside Amelia, his balls pulsing slightly as he filled her up.

Beth had already taken her position over the back of the sofa, ass out as Mark pulled his, still half hard dick, out of my girlfriend. He pushed me away as he lined himself up and penetrated Beth. Amelia gingerly stood and smiled at me. She grabbed my hand and pulled me over to the over sofa where we sat away from Greg.

"I'm sorry I didn't tell you," she said innocently as she undid my belt.

"It was a bit of a surprise," I admitted, almost in a trance as she pulled out my dick. Mark was still ramming repeatedly into Beth who was moaning happily. I didn't realise what Amelia was planning to do until she had lowered herself onto my dick.

"Wait-" I tried to stop her but I was already inside before I could protest.

"You need to reclaim me," she said with a put as she started to fuck me. As much as I hate to admit it, she felt amazing. I could feel Mark's cum lubing her up and there is no way I could have stopped her from bouncing on my dick.

She started moaning, although I couldn't help but notice that it wasn't the same kind of animalistic moaning as when Mark had fucked her.

"So, out of curiosity," I said, trying hard not to cum, "Do I get this for my birthday too?"

She just laughed at me as she continued to fuck herself on my cock.