The immensely pleasurable act of taking a large shit and proceeding to go to bed directly after. The expanded anal sphincter, aka asshole, when combined with the normal force or the pushing up of the bed, provides a very sensual and pleasurable experience.
James Woods: I'm gonna shitsleep tonight.
Peter Griffin : What did ya have Mexican for lunch?
When it's coldoutside and you gotta go lay some cable, and when you finish and wipe that shit up the sleeve of the sweater your moms knitted you gets some unwanted secondary ass wiping action.
Dude 1: Dude, I just hung one out and when I was wiping my turd cutter things got messy... check out my Shit Sleeve!
Dude 2: Dude, that's nasty, change that shit out and let's go get some tacos.