If it's a slin pin, it's max of .5in long, just pinch and inject all the way, make sure it's sub-q, not a skin-pop. There shoudn't be a bubble on your skin after the inject. You need to preload the syringes and refridgerate them after reconstitution. If you just leave and open amp in the fridge it's much more likely to get contaminated. If you happened to have an actual sealed vial of HCG( I have one of these right now), then you could just reconstitute, refridgerate, and draw and shoot when needed. HCG rarely comes like that though, so pre-loading is a little more sterile, as the syringes aren't open to the air like an open amp is. You can inject the HCG any where in the abs... just not in the same spot every day, move it around.