Whilst changing your diaper, Wendy noticed you were touching yourself. Instead of being angry, she shows you how to masturbate properly. First she guides your hand onto her breasts so you will get really hard. Next she guides your hand up and down your rock hard stiffy. She uses her own hand to show you exactly how she wants you to do it and even SUCKS YOUR STIFFY. You are so horny and it feels so amazing you want to explode. But just before you do, she takes your hand off your wee wee and finishes putting on a new diaper. You are denied your orgasm. You can only cum when she says you can.