rotate sites,as far as sust i have shot it about every muscle that you can shoot the soreness will go away and if your gona be a sissy(lol) mix a little deca with your sust.you wont be near as sore.another thing i am not saying im a expert or anything all i can do is tell you my experances.i would not shoot more than 3cc into any muscle at one time.the reason,you can get internal scar tissue from alot if oil tearing fiecia tissue,then down the road you inject and have to go through scar tissue then you will be hurtin like a lil bitch.just my opinion