Oh, good idea. Hmm, nipple clamps directly looped around the wand? Or maybe using a bungee cord...so there's some give in it, and the degree of pulling force varies? In addition to that, something to make the huge dildo vibrate would certainly be a nice bonus, and probably further limit the time he has to get all the way down before he cums. But the further down he goes, the more he'll probably feel the vibrations deep in this ass if the vibrations are coming from the base of the dildo. Or do you think that's a bit TOO merciless for him? ;-)