Why does my health teacher tease me?

my male health teacher has always teased me and hes still doing it when i visit his cl room in the morning b4 homeroom and people say that im his teacher pet and i don't mind being one and he never admits that he teases me and i have always ben his target ever since i was in his health cl when i was in 10th grade and i still am and he is 27 years old and i don't know y he keeps on teasing me