What should I do about this girl?

I have a friend who is a little chubby. One time at a party, she put her big butt in another girl's face and let out a HUGE fart. Then she said "Whew! That one was spicy!" Then, every time we would be with another girl, she would always belch or rip a fart in her face. One time she held this girl down and put her jeans-butt in her face and had us time how long the she farted up the girl's nose. 14 seconds. Not many people like her except for me. One time when someone made fun of her, she got on top of her, opened the girl's mouth and blew a windy fart in her mouth. What should I do?