Every now and again a filly may do something that requires a true punishment. Not something fun, but something they truly hate.
Here are some things ponies hate that can be made into punishments and not funishments.
Head hair cutting/shaving/etc.
Eyebrow plucking/shaving/threading
Body part waxing instead of normal shaving
candle play
cramping enema recipes
my I REALLY DON'T WANT TO...