Many politicians wear religion 'on their sleeves'. [=show their religious beliefs in a very open way]
The mayor's critics were 'laughing up their sleeves' when news of the scandal was first reported.
He 'wears his emotions/heart on his sleeve'. [=his emotions are easy to see]
(..) Why don't you relax, and take your jacket off. I can't. I have a tendency to get chilly. How masculine. Plus I'm wearing short sleeves. I don't want to expose my tattoos. She's unbelievable. - Hey, this guy says he know Bricker. - Oh, you know Bricker? From where? What's going on here? (..)1990 TvShow: Seinfeld Title: The Stakeout Season: 1 Episode 2