Mathematical

"It's, it's so big," he gasped.

"Really? I'm only like halfway in," she murmured, her voice shaking like she could feel it herself.

"Oh my god. How much lube did you use?"

She chuckled softly. "It's kind of thin at the tip, but it gets bigger on the way down. I've never had a complaint yet, it's my favorite."

"I, oh, I can see why," he gasped, as she drove it gently further.

She continued her slow, agonizing dive inside him, until at last he could feel her hips pressed fast against his cheeks.

"How's it feel?" she whispered in his ear.

"If you touched my dick I'd start coming right now," he mumbled as coherently as he could. Every breath he took made her strap-on jerk inside of him, and it was filling him more completely than anything he'd ever had.

"Fuck, it feels like it's a mile long. How big is that thing even?"

Instead of answering, she slowly started to pull out, almost to the tip. He made a soft whining sound when suddenly she drove it back inside of him, faster than before. He moaned again, and she repeated the process, hilting her dildo inside him with an impact that made his entire abdomen clench.

He braced for her to continue, but she remained motionless. He shifted gently and whined again.

"Why did you stop?"

"Beg for it."

He blinked, behind the blindfold. "What?"

"Ask me to fuck you. I want you to beg for it."

"Wait, really?"

"Come on, just do it? I have an audio kink, okay."

"Uh, alright. Please, please fuck me, Alyssa."

She pulled back and shoved once into him hard. "C'mon, you can do better than that."

He sniffed. "How about you start first and give me some inspiration?"

He felt her shrug, and then pulled out about halfway. As she thrust back inside, he started to moan again.

"Fuck, Alyssa, that feels so big. God, I wish that cock was real. Please fuck me. Please fuck me, pleeease."

He wasn't sure if it was exactly what she wanted, and he felt kind of silly, but as soon as he started to moan the word please she started giving him longer and harder strokes, and soon he was enthusiastically encouraging her to fuck him harder and harder. Soon he found himself unable to make words as she wrapped her hands around his hips and shifted into overdrive, her cock slamming into him hard enough that all he could do was moan and shake beneath her.

Suddenly a terrible emptiness was all he felt, as she yanked her dildo out of him. He protested weakly, but was cut short when suddenly she grabbed his leg and flipped him over like he didn't weigh a thing. Alyssa gripped the underside of his knees and pinned them up by his shoulders, her strap-on gliding straight back into his open asshole and her balls slamming against his cheeks as she picked up her pace exactly where she'd left off. She leaned down over him and without a word she began kissing and biting his neck and collarbones. He reached down to stroke his cock, desperate to come, but she reached down to grab his wrist and pin it above them without breaking stride.

"Please, I need to come," he begged.

"Then come for me. Come from my cock. I want to see you come from me fucking you."

He clenched up again, her merciless assault not missing a beat, and between the fucking and the biting and being held down he suddenly felt the urge rising inside him.

"!!" he gasped, and then it was on him, a deluge splattering out onto her breasts and his chest. She suddenly broke stride and started to seemingly convulse, herself, gasping and slamming him a few last times herself before juddering to a stop.

She pulled her dildo from inside him, and his legs dropped back to the bed in exhaustion.

"Wow, I," she started mumbling, "I think I just came watching you come."

Still gasping, he couldn't respond.

"Okay, I'm gonna get cleaned up. You stay put. You're gonna need a shower after that."

He grunted his agreement, still blindfolded but too tired to react.

She left the room, and he passed out, still dazed, but definitely satisfied.