A bonerdoner is a guy that a girl, usually very attractive, elects to have pre-arranged sex with her one or more times just to get over a relationship/bad test/daddy problems or just because she is extremely horny at the moment. A bonerdoner differentiates from a fuckbuddy in that they do not necessarily have to be friends, nor do they have to have sex more than one time.
Julia: So, did you get a bonerdoner for the big weekend?
Paulina: Yeah, he's some rich Harvard guy.
Julia: I heard Harvard guys have small dicks.
Paulina: Well I guess I'll find out after this weekend, I mean, he's just a bonerdoner, so it's not like we're attached.