I [f]ucked my best [f]riend and took her virginity

This took place a few years ago, but I’ve wanted to write about it ever since.

To introduce myself, I’m Alex (not my real name for obvious reasons). I’m bi and I’ve been out since I was a teen, and I’ve been best friends with Kasey (fake name too obvs) since early high school.
I used to be a bit overweight but I slimmed down a bunch at uni, and I’ve had short hair forever. I’m also tall and admittedly pretty confident, so I’ve been relatively popular with both ladies and guys since early adulthood – nothing ridiculous, but definitely capable of hooking up with whatever gender I want when I go out. Kasey is pretty curvy, and only came out as bi after high school. She’s pretty cute – I think I had a crush on her for all of two weeks when we were about sixteen, but never any serious feelings or attraction – but quite shy when it comes to dating or making a move on anybody (and a virgin when this happened). In fact, only a couple of months before this encounter, I learnt she’d never had an orgasm – something unthinkable to me, who’d been jerking it on the regular since I was young due to a high sex drive. We went to a sex shop and I helped her pick out a vibrating dildo. At first she couldn’t quite get it to work, but when she did … she thanked me a lot. ;)