A sub I had some fun with could count in several languages. So to make things more difficult, I made her transfer languages mid count, as well as doing math as part of the count. The counting was done to each impact of a cane on her ass.

That's just one example.

I also had a submissive who was a wordsmith. So I had her write several papers, and then read them to me as I paddled her butt. Any mistakes or pauses in reading resulted in more pain.