Hi, Thanks everyone for the lovely responses. I particularly like Mistress Sophia Katz's solution of having some unpleasant punishment for safewording. When I'm topping my girlfriend I'm pretty mean, and will often be able to bring her to tears. I'd like to be able to experience that for myself. And I think she also gets frustrated that her times as a top are often cut short. Punishment for safewording is something she's been suggesting actually, as she points out "you shouldn't be safewording if you know something is safe". Two of the quickest things that will make me safeword are clover clamps on nipples, or caning. I actually love both and they're both something I fantasize about, and I usually regret not going through with it soon after. We discussed not having a safeword for caning, with a small number of strokes. I think at the root of it I get scared that the pain is so bad that it must be dangerous, or I must be bleeding or something.