A Rhino slap is a very powerful slap, the way to perform a Rhino slap is quite easy, simply pick up a wellington boot or any old hiking boot and while your friend is asleep, do a run up from across the room and slam it extremely hard into his/her temple or eye area, this should wake him/her up, and while they are screaming and confused, looking around, swing the boot extremely hard in their mouth area, then run out of the room.
Alfred: "Daniel did you see me slam my boot into Ned's face while he was asleep yesterday!?"
Daniel: "Hahaha yeah man, Jorge recorded it you completely knocked him the fuck out.'
Cassandra: "I thought I heard a sound last night, I thought it was a gun shot! Nice Rhino Slap Alfred!!!"