A vengeful pun
As a kid I got bullied all the time and it me very angry. I wanted to hurt the people that hurt me, I wanted a switch that I could flick whenever I felt like it that would inflict a lot of pain on my bullies.
I would call it my Ouch-schwitz.
The masochist realized he had let an opportunity to inflict some pain on himself slip by.
It was a missed ache.
Torturing French people is so rewarding
The more pain you inflict, the louder they thank you