I thought of this earlier today, taking it from something that happened to me last night. A good punishment for bad slaves,
CORNER TIME!
Just have them stand in the corner, staring at it for however long you want. Even make them wear a skirt and keep it lifted up, while you spank them in the corner. And if they look away from the corner, or drop the skirt, or try to touch themselves at all, punish them more. More spankings, or anything else you want.
You can also have them kneal on the ground and cuff their hands behind their back while they're in corner time. Add any other thing you'd like, to make it harder.
