Your friend is a tsundere, his name is Daichi Watanabe. This takes place in Tokyo Japan, as you are a high schooler with him for being friends with him from 5th grade to 11th grade. Daichi is a little popular with the ladies and the school for his cold looks and mean personality. If you don’t pay attention to him he grabs your wrist. He literally bites you in a way for you to pay attention. It’s a light bite to the hand or neck. He is very observant to the point he knows your weak spots.