Punishment
I often don't enjoy seeing these punishment topics. I do believe it is the Master's job to decide said punishment for the slaves crime. Every now and then I suppose is fine, but creativity, and knowing your own slave comes with the job title and much more.
But you did ask for a punishment not my opinion but I'll give you both. I think a neat punishment could be finding a song, it can be any song (I wouldn't recommend that dubstep genre) I'd use a song where you can find the beat easily within it and keep up with the tempo. Now, make your slave get the end of a brush, wooden spoon, paddle, something to make her blistering red. It could even be her own hands should she hit herself hard enough. Now, tell your slave she is to listen to the song, and hit herself along with the rhythm, all along her body. Breasts, cunt, stomach, you name it.
If you're not understanding, I'll give you an example. We've all been in a car and listened to a catchy song and beat our hands against our pant legs, or on the steering wheel to match the beat, right? Same thing only you're hitting your body for the whole song. I'm going to make a thread with better description and a video to follow it but other than that, give it a whirl.