Mansleep Share definition Flag A sleepover that consists entirely of men. (Not to be confused with a gay orgy). Man #1: Hey are you going to the mansleep at CJ's house?Man #2: Yea bro I'll see you there. Mansleep by Mansleeper February 24, 2011 0 0 Get merch Get the Mansleep mug. Buy Now — $32.95 See more merch