Does anyone else have a farting reflex?

It's something recent, that each time I flinch or someone makes me flinch I just bust out. I thought it was nothing at first but then it started getting serious. It started off with mild gas and it went off from there, now I'm just kind of . But it only happens when I flinch, like if someone makes a loud sound or act as if the're gonna punch me. I looked it up on google but found nothing, and I was wondering does anyone else have this problem or heard of anyone with it? And if so what did they do about it?