So this challenge - it would need to be for all genders at least it seems. I guess what I'm thinking is - how many people can any one challenge appeal to? As you'll see in my profile I like anal play (and everyone has a derriere!) but its not everyones cup of tea, likewise if it involved clamps of various sorts and so on. Perhaps one of the many interested subs there seem to be could relate something their dom(me) had previously made them do, and challenge the other subs to do the same?