A sleep suck-gasm is the cumgasm a guy has when he fucks a guy in the mouth and has a cumgasm while he's asleep.
Matt occasionally has a sleep suck-gasm when he fucks my mouth and has a cumgasm -- I can always tell though, because I have his cum-taste in my mouth afterward!
When you think you need to take a dump, go and sit on the toilet for minutes, nothing comes out, so you stand up and leave feeling somewhat unaccomplished and awkward.
Geoff: Dude I just took a 3 minute sitter
Bill: I know how you feel, I had an Anti-shit-gasm myself this morning Geoff: Did you flush? I never know whether to flush