jacklegged
A person who farts on someone's leg. They think it's funny. They are not funny. They are a jacklegged.
My brother is a jacklegged. He farted on me during class and laughed about it.
My friend's dad is a jacklegged. He farted on my mom and said it was a surprise.
My little sister is a jacklegged. She farted on my dog and called it a prank.