Verb conjugation of "zappeln" in German

Since my wife is pregnant, we must postpone the trip until tomorrow. I am back again in Poland in June and then I would be very happy to meet you. I will email the exact dates a little later.
You have to be careful when you go on summer vacation. There are many dangers but the most dangerous one is the sun itself, because if you're not careful it may harm you. People underestimate the rays.
Thank you for your email, everything was crystal clear. We should call each other, this would be the best way. Do you have the same opinion? But I think I need more help, for example: how do you conjugate swim?