What will break Wolf? (Patreon)

Hi there!

I need some suggestions! ^^
So, for the comic I'm planing on having fox discarting the feathers to use his hands and claws: that should bring some louder giggles from Wolf.
However, what kind of method/tool should I reserve for the end? Something that would bring Wolf to the edge of insanity if used on his pathetic soles?
Comment below as I need ideas!

Thanks a lot! :)