Some guys like pain, I guess. I saw an episode of "Cathouse" a few years back. There was a guy that paid like 5 or 6 of the ladies at the Bunny Ranch to put on high heels and form a line and walk on him from feet to chest and keep the train rolling. I was amazed. He must have spent a fortune on that many of those ladies just for that!!!
Another guy paid a lady to lay in bed and play chess with him naked for an hour! Whatever.
As for the teeth thing. I used to be with a girl that would rub her front teeth up and down the shaft. It would actually leave brush burns. No teeth for me!