when you hold a fart in for so long that it squeezes through the closed butt cheeks making a popping noise when the butt cheeks hit eachother on reclosure
"eww what is that smell??"
"what was that sound??"
"sorry, i tried to hold it in but it ended up a tooty booty"
a girl with a cute little butt.
Girl you got a little tooty booty.