Reminds me of what I used to do in high school gatherings/parties.
I'd slip off into another room where no one was around, I'd make a big "bang" sound, and then hollar in pain. I'd hunch over, and when people would rush to check on me, they'd be like "What happened" and I'd respond with....
"I smashed my thumb"
Before they'd check on me I would unzip my pants, carefully take out one testical, and try to hide the frank and other bean. I'd position my testical over my thumb, to make it look like my thumb was as big as when cartoon characters hit their thumb and their thumb expands.
Initially people's eyes got real big thinking it's my actual thumb, but then they realize they're looking at my nut.
It was very funny, I hadn't done that in years. I should bring that party trick back.