Yah, I found myself doing the same.

I had some previous training, though... in Army Boot Camp we were given "remedial training" (Read: pushups!) if the DI saw us with our hand in a pocket.

We learned to tuck a thumb in our belts, or, sometimes, to tuck our fingertips under the belt from the bottom, and let our arms droop from there. (I know, sounds weird, but it works.)

So if you have a belt, or a belted pouch, you could try that. Otherwise, yep, arms-crossed here, too!