What is Skinny Fuck?
1.
A hook up with the sole purpose of raising one's self-esteem.
A person (usually a girl) trying to fuck someone so that they can reassure themselves that that look good/are still skinny enough for others to desire them.
"Did you hook up with John last night?"
"Yeah, but it was just a skinny fuck. It didn't mean anything and now I feel better knowing at least John still wants to fuck me."
See
