i found this on my left thigh while applying moisturizer late last night...

then i recalled...
Brayden: Sheryl, I want go toilet.
Sheryl: Alright! Let's go.
Sheryl: Amanda, i'll be back soon! You stay with laoshi.
Amanda: No! I want Sheryl to sit with me...
Brayden held my left hand and Amanda held my right hand.
Both began to pull me against opposite directions...
Brayden wants me to bring him to the toilet, Amanda wants me to stay in class with her.
......
then, i hit my left thigh against the door while trying to escape out the class...