a sound that comes from an older person as they pass gas and air rushes out of their anus and between their soft, dough-like buttocks. can also make a flippity flappity sound.
grandkid 1: man! grandma farted!! did you smell it?
grandkid 2: i didn't just smell it, i felt it! i was sitting right next to her when she did it! i felt those flappity cheeks vibrate through the couch!
grandkid 1: then she just glared at everybody and said what the hell are you little bastards looking at? she didn't even care!
grandkid 2: i know!! i love grandma!!!
grandkid 1: let's give her some beans maybe she'll do it again! then we can record the sound coming out of her!