When I go to the dr for my bi-weekly trt inject, they NEVER aspirate - i think it is debated in medical circles for IM. I probably would if using tren, since tren into a vein might be what causes tren cough, but i doubt i ever will ever use it. The thought of experiencing that scares the crap out of me. But I digress.
Delt is a hell of a lot easier than quad in my opinion. I go straight in the side, about 2 fingers down from the shoulder. Hold the syr like a dart, put your wrist against your arm and push it in. for me, this works a lot smoother than going in from mid air. I use either a 23g or 25g 1" in delts and hip without issue.