Bowl it up, Get her to strip!
Pull down the "Joy" Stick and release the bowling ball when the meter is green and in the middle. Putting spin on the ball is pointless. Aim straight!
(there's a pretty obvious sweet spot, release it there and you'll get a strike every time)
Unlock a new a "strip move" every 10 pins. You can rewatch moves by clicking the numbers on the right.
Also note, there's plenty of hidden rollovers and clicks on the girl
(smack her butt, make her shake and rock, etc)