I'm speaking only for myself here, as a guy who would no doubt be considered "too gentle" by most of the people who've contributed to this thread.
I would respond very, very badly to most of the suggestions here. I mean, it's all very well that some of you enjoy role-playing; I would not. I am also unwilling to inflict pain. I just don't play that way, and would recoil at the suggestion that I try.
I'm fortunate to have a partner who puts the same value on equality and gentleness that I do. If she needed roughness, I would encourage her to find it elsewhere.
Isn't part of the point of polyamory that I don't have to be all things to one particular partner, that I don't have to change deep-rooted and, frankly, non-negotiable things about myself to fit someone else's mold?
"Ignorance more frequently begets confidence than does knowledge" - Charles Darwin