My teacher constantly farts in lessons :/?

what should i do? she stands up by the board and starts rabbiting on like teachers do and then all of a sudden she stops and farts... sometimes there really loud and smelly :/ sometimes there silent but violent, it distracts everybody learning and mine, but i cant report it can i, going over to the headteacher... excuse me sir but My maths teacher keeps farting, what to doooooo :|