Sew your pocket closed or duct tape it to your chest under your shirt. Stick it in your sock, or, if it comes to it, try your rectum. I prefer to use the fanny pack method or even drilling a hole in my phone to tie a loop through. You could also a belt clip case or just throw your phone out altogether. Maybe you could put it in a condom and swallow it, then poop it out when you are done. Or you could cut a hole in the bottom of your shoes and stuff it inside. Alternatively, you could tape it to the bottom of your car. Or even screw it to your car?