dominance
I immediately distrust anyone who says "I've never done X, I'm a dom(me)". The kind of insecurity behind that statement means they should in no way be allowed to dominate anybody. You have to be able to empathize with anyone below you, whether the context is sexual or not but especially if it is, and refusing to experience what you are dishing out to someone else means you can't empathize. You don't have to enjoy the experience but you should be open to it for informational purposes.