ha ha ha ha,,,i remember when i had my first sust inject the next 3 days i was limping and i told everybody that i pulled my hamstring, i havent used sust in yrs but when i wanna stop the pain w/prop i loosen the inject area by rubbing it i then put the needle under the faucet on hot for like 5 mins to make sure its warm then inject slowly and rub the inject area afterwards..hope that helps since prop is in sust afterall...