My girlfriend came up with a predicament bondage idea last night. So I was tied up and gagged and she was straddling me. She had a wartenburg wheel and a silicone pastry brush. Prior to this she had edged me for a while, so I really wanted to finish at this point. She rubbed the pastry back forth just in front of my penis, so that if I thrust forward it would hit my penis. This was a very pleasant sensation and was potentially enough to get me off at that point in time. BUT in front of the pastry brush was the wartenburg wheel, so if I thrust too far my penis hit one of the prongs and that was not fun. Overall a very fun experience.