Oh yes...welcome to my world. I have shaky hands too and I don't even drink caffeine. What helps me is that I use my other hand to stabilize my piping hand. You can see a bit of this in the video. It really does help. Also, try not to fill the piping bag super full. It makes it harder to pipe and gives you less control. Plus if your icing is too thick, it'll make your hands shake even worse. Just know that you're not alone.