I want to pledge a fraternity but I'm afraid they'll make me do this.?

I went to a Beta pledge auction and the pledges stripped down to their underwear and gave lap dances to girls. I'm on the heavy overweight side. I'm scared I might have to do strip do if I pledged and any other almost naked activities. But I still really want to be in a frat for brothers and friends. And besides, I'm scard girls might make fun of me if I stripped. What should I do?