V.W.
I agree. I also don't want to hear it if it isn't "for a laugh". In those cases, you can take care of it quietly with a polite excuse me, not just let it rip and then acting proud.
Believe it or not, my DAUGHTER started doing this. I had to get on to her a lot about it. It was like some weird phase she went through about a year ago. She is 11 now, so in 5th grade or so. Maybe she picked it up from the boys at her table in the lunchroom? I never really thought of that. We certainly don't do it at home (not me, my husband, nor my son--who is 3 years older than daughter).
It's just gross. And I find no excuse for not using polite manners.