A sorority girl who gets dared to fuck the virgin 'nerd' and has to take pictures to prove it.
A 40+ year old prostitute or family friend/secret nympho that wants to let him try all of the nasty stuff in his mind on her.
Or lastly, a cheerleader that allows him to do more and more sexual things with her in exchange for tutoring and doing her assignments. Starts with jerking off while she talks to him/handjobs and obviously grows in to much, much more.