I have 3-4 different spots on the quads that I alternate. I also hit the delt's and the tri's. I know a few that do the biceps, but not me! If you are doing something like Tren. and are EOD or ED you need to move them around. I also will draw the oil based stuff out with a 25 guage, then take an insulin dart, pull the plunger out, and squirt the oil into the dart. Then place the plunger back in and turn right side-up, tap it a few times, to get the small air bubbles out, and you are good to go!
Always pull back on the plunger on any sot to be sure you have not hit a vessel. A
PS: When using the insulin darts, be sure you get it in the muscle, so the areas for that need to be LEAN! I don't know how advanced you are, some feel that beginners should not go anywhere other than the glutes. Not saying you are a newbie, just looking out for you. And I know how that pin cushion feeling is! I had so much scar tissue back in the 80's that I would hit the scar tissue, and bend the dart! OUCH!!! A