All Comments on 'Unexpected'

It's fine for a first story, the sex is firmly but gently described ("intense, hard, and almost frantic"). I'm on board with any story that has pale peach French knickers!

I would like a bit more to the story, for example if Rob and Ava were somehow enjoying an illicit relationship - they seem to be keeping quiet only out of modesty. I don't know which aspects your editor has dealt with, but punctuation overall is not good, and there are a few typos. (It's 'platonic' because of Plato.) Please keep writing if you enjoy it, and perhaps deal with the punctuation and construction of dialogue to make it easier to read, e.g.:

"Well, don't take too long, birthday boy," Nick replied. "You're missing all the action."