is it safe to 69 with fat girls?

so this fat girl wants it but my youth group leader says to never 69 with fat girls because they have bad gas from all the fat and bad discipline so they will most likely fart or even shit a little in your face.

Drinking water helps quite a bit. I try to defecate in the morning so I don't have to worry about it for the rest of the day. After breakfast, preferably.