Open Sleeman Share definition Flag Having anal sex until the person's asshole is gaping and then peeing in the gaping asshole. We were having the best anal until I couldn't hold in my pee any more and accidentally gave her an open sleeman. Open Sleeman by jinjabread_man May 8, 2011 0 0 Get merch Get the Open Sleeman mug. Buy Now — $32.95 See more merch