Me, Inwould avoid the whole problem and remove the pocket from the clothing - I have a lycra-like arm and that holds a phone for jogging and it is useful enough

Me, Inwould avoid the whole problem and remove the pocket from the clothing - I have a lycra-like arm and that holds a phone for jogging and it is useful enough that if I could just slap it onto any piece of clothing and it would stay then I have a pocket I can put onto any clothing i want at any location