This is used all though my school. It basically means that someone is So Super humanly fast with movement, Actually Slapped the shit out of Someone to the point that they are sleep as Soon as he turns around. This Term was connected to a Now Blocked Video on YouTube Where it has Travis Scott's Goosebumps in the background playing and as Soon as the man Slaps him it goes into Slow monition to where Kendrick say "..The PUSSY TO DIE FOR!" Because the guy Immediate swiped his girlfriend off her feet and ran away with her.
The Character Itachi Uchiha is from Naruto and he was named the strongest of the Uchiha clan, with this he was quick. This Phrase is Simply putting a Red Flag on someone because of their Brute strength while being able to keep Unbelievable Strength all at the Same time having a Motivation to get somewhere without having to fight a nigga.
A sneeky way you can enter your partner, lover, fuck buddy, or whoever, when they are alseep either in the vagina, arsehole, mouth or wherever takes your fancy. Just make sure they don't wake up otherwise you'll just end up looking like a deviant.
Anthony: Hey man, I waited up last night until Karen fell asleep and sleepslammed her good.
Phil: Ah cool, serves her right for not sucking on your ballsbeforehand.
Anthony: Yeah, lucky she didn't wake up because I had my nuts in her arse.
When you decide to stay in bed to escape the problems of the real world. Actual sleep is not necessary, simply lying on the bed doing nothing is enough.