Guys see a nice arse. They say they'd like to "tap that". Guys see an eightball close to the left side pocket. They think, "Hmm, better just tap that". But it doesn't mean they wish to perform sexually explicit acts with the ball on the green, lush felt covering the table. Or maybe they do? Or maybe they're confused? Or maybe it's just an expression? Or maybe there are things in this world we just don't understand?