Yeah, that's the problem - when you get kinks that flat-out make you uncomfortable, it starts making the challenge stressful instead of fun. And then it defeats its own purpose, because the whole reason you're participating is to have fun!

One thing I've always throught the KB mods should do is allow you to set your kink preference level - Mild, Moderate or Extreme. Mild would include common kinks like spanking and bondage. Moderate would take it up to the level of things like whipping/flogging and double penetration. And they could put stuff like fucking machines and queening in the Extreme category. Make sure everyone can enjoy it, no matter what kink level.