Oh, you kids!
Stephen is in Germany, where they drive on the right (correct!

) side of the road and sit on the left (correct!

) side of the car, so, arm signals are with the left arm, so, no need to let go of the throttle. Unless they are different from the U.S, left arm straight out equals left turn. Left arm at a right angle pointing to the sky equals right turn. Left arm down with palm facing backwards equals slow or stop. If you are in the UK or other wrong-sided countries

, you might try this, who knows, someone behind you or coming toward you might get it.
I suppose it is possible that other countries may never have had arm signal laws or have abandoned them, thus some people may have never had the joy of the window being open. So, for all of our teenage members

here is a picture for your ready reference.
Richard L.