But honestly I cam imagine that many of those guys participating in slapping tournaments do take pain suppressants in advance. It would even make sense from a performance point of view. Or maybe, maybe if you get slapped you feel so much pain that you go nuts even harder when it is your turn!
That's possible but where to know those rules from slapping tournaments and to know if those participants aren't taking anything to take advantage of their opponents? this is very new but it's fun to watch although myself cannot attain to be slapped in the face.
Indeed, strengthening the jaw and neck will likely make them able to withstand a hard slap and is not a good reason for you to relax to receive a slap, it will just bounce you off easily. Strengthening yourself with drugs I don't think is the right way, because if you use it every day then of course it will have a bad impact on your health from time to time, diligent exercise and discipline are the best ways for an athlete.
Using drugs with such tournaments aren't really allowed but if those slap tournaments allow it then for those participants, they won't hesitate to take it. But if it's not, they won't.