rhinoceros horn
when you bang a chick so hard, your dick comes out her back. It is the most extreme of all banging.
"dude she feels so sore after last night, do you reckon he gave her rhinoceros horn?"
Three-Horned Rhinoceros
Obviously, this is when 3 men engage in sex with no woman or additional parties.
Hey Steve, you comin' 'round tonight? Me and Jim are trying to set up a Three-Horned Rhinoceros....just need one more!