I’m not sure if it’s a movie or a story out of a book.
Basically there is a traveling sideshow with circus freaks. One of the freaks is the worlds fattest lady. The protagonist is standing in line to get a blowjob as today she is blowing everyone in the carnival.
He gets his blowjob but she is spitting the cum on the side of her bed. There’s a big ole puddle of it. He slips and falls on his ass. She starts laughing at him.
He gets mad and yells something like “at least my mouth isn’t a public toilet!!”
End scene as he runs out of the circus tent.