Ribzuba 

The act of ejaculating on the ribcage of an anorexic whore, and then offering her payment in the form of an apple pie.

Dude, I totally gave Susan a ribzuba last night; she was even cool enough to share the pie.

Ribzuba by Arthur T. Read July 6, 2008

Ribzuba 

When a person plays another person's ribs with their fingers while also playing their butt like a tuba.

Cody: What instrument do you play?
Matt: I play the ribzuba, man!

Ribzuba by Barneybacktrack March 18, 2009