I was doing some karate the other day at the studio.
They kicked me out because I was doing “kungi fui.”
Kungi Fui
Explanation
Explain Bear
Listen here, buddy. This joke is funny because the dude was trying to do karate, which is a real martial art, but he messed it up and said "kungi fui" instead, which is just a silly made-up term. It's like you trying to cook, ending up ordering pizza, you silly goose!