yama - donīt ever let anyone make you think of yourself as a "bad sub" just because you cannot/will not participate in any particular action.

It takes all sorts. All subs I met in real life are into different things. Some of them are not even masochists at all. There is no such thing as a "real sub", and please steer clear of anyone who tries to make you believe that.
Such statements are usually made by wannabe doms who donīt care about your well-being, and they use those statements to force you into an action they like, while you donīt like it. No one has a right to do that. (I am talking about hard limits here. Soft limits should be tested. If it is something you have never done, but are curious about, go ahead and try it. I donīt remember how many things I thought I would not like/could not bear, and hubby proved the opposite. *g*)

As for the clamp/clip thing: I can bear clamps (alligator clamps) on my nipples, and on my clit, but not on the pussy lips. It just feels wrong there.

The only persons who have the right to decide what is right/important in your relationship is you and your partner. Not anyone else. There is no such thing as a BDSM relationship rule valid for all. Except, maybe, that both/all partners in a relationship should be comfortable with whatīs going on.

But that should be understood by common sense, and be made sure in any relationship - BDSM or vanilla.