Help with little brother dilema - girls only?

I'm 17 and i have one brother 12 and his friend who is just like my lil brother (because he's over all the time) still think farting in people's faces is funny! He and his friend have gotten me a number of times. I told them next person who farts even near me, im going to hold down and rip one on their face....is the threat enuff or should i make good on my threat to try and keep these lil fart machines away????