Returning a sexual
favor either to an intimate friend of the opposite sex or from a same sex friend or partner. Sometimes a trade of a second party sexual favor for value or renumeration.
A sexual act with an ex-partner.
I was going to kill that shitbag but he delt me his sister as a fuckback so we're cool now.
Marispan got drunk and we ended up in a fuckback for old times sake.