Spanking bet

I had a math test at school. I'm usually not good at math, so I had to study a lot and was worried about how I would pass.
On top of all that, my stupid brother @Pit04 had to tease me about how I didn't know anything and how I would definitely fail the test, which really annoyed me. So I offered him a bet that I would definitely get a 3 or higher grade on the test.

A couple of days later when the test results came in, he regretted it a lot. I did the test quite well and got a 4 (B according to the American system), which made him not happy at all.
Since I had 77 points out of 100, that meant he would get 77 spankings on his bare ass with a wooden spoon. So that day I followed him to his room to deliver him well-deserved punishment.
After I spanked his ass well, he had to apologize to me for not believing in me.

After that, I thanked him for giving me the motivation to study hard and offered him that if he thought the same thing next time, we could make a bet like this again.
But I think he'll hardly want to do something like this again. 😀