eau de arse - the smell that comes from someone’s butt when they have been

the smell that comes from someone’s butt when they have been sitting too long and forgot to take a break

My friend’s eau de arse was so strong it made the whole bus turn around.

At the park, the eau de arse from the bench was so bad I had to leave.

During the test, I could smell eau de arse from the person next to me.