I was in the bathroom when someone came up to me and asked me if I wanted to cross swords. He then started to swing his penis at me. That's not koo I said, so to defend myself, I swung my penis back at his. He took much pleasure in crossing swords.
A form of male bonding. When two males share a urinal or toilet bowl during urination, the two males cross their pee streams in a manner to harken to the act of crossing swords in battle. They may even have pee fights where they trade stream hits much like jedi trade lightsaber blows.