I want to make fun of my boyfriend's tic
Why? Has he made fun of something about you?
No, but I have heard of people making fun of it
You shouldn't make fun of your boyfriend's tic. It's just hurting him over something that he can't control.
What's wrong with making fun of him?
Your boyfriend is someone that you care about, so you shouldn't be trying to cause him pain in this way. He can't control his tic, so what would you gain from ridiculing him?