For me it's the adrenaline rush. The look on his face when I know I'm in " trouble ", the pounding heart, if im feeling especially cheeky I'll stick my tongue out or wiggle my bum at him! Then it's a chase. Me running and him always catching me. The struggle to hold me down. A sub needs rules and limits set for him/her and knows there will be consequences for not obeying them. If there are no consequences then how can they feel the control they long for? Accepting a spanking where the focus is on correcting behavior rather than for pleasure is proof of submission to you. It makes your control of the sub very real. It's not just as a punishment, it can all be for pleasure or part of a scene. There's just a rush of adrenaline, I always squeal. A very important part is trust trust trust. And that its FUN. It's not really a punishment as you'd know it. It's all part of the fun with a D/s relationship. I do it because I enjoy it!!