There’s a lot of pressure to “be funny” when doing improv. Especially if you’re performing on a stage, with lights and a paying audience. People paid real money to see some funny, so you’d better be funny. That’s a lot of pressure.
Unfortunately, this pressure makes us not act like normal humans. The term we improvisors use is “getting stuck in your head.” Thinking too much. Worrying about what witty thing to say next, or funny face to pull instead of being present in the moment. What you should be doing is; Listening with your eyes and ears. Reacting to your fellow performer like a human.
When in doubt, just react like you would in everyday life.
Forget there’s an audience. Forget that you want to make funny. Just be REAL. If a girl asks you to dance, do what you’d do in real life (ie. look shocked, stutter/mumble something like “mmoohokey”) Don’t bother trying to figure out the funniest thing to say at the moment. Just do what you would do. It’s both the easiest and most difficult thing to do.
You instinctively know how you’d react in most situations, if you allow yourself to really listen and be there. (pro-tip hint: most of the time the most human reaction is to not say anything.) If you react like you normally would, that means you’re reacting like a human, and you’re performing in front of humans. They LOVE that. They love to see people acting like real people.