Honestly bro anywhere in the muscle seems to work, I usuallypin about an inch above my nipple. Only holds about 1.5 cc without shifting tissue. So if you're pinning barrels I'd split it into two shots. But it's one of my favorite spots
Pretty much anywhere you can feel muscle, some people prefer upper chest more but I'm pretty vascular up there so I prefer it about inch or two above the nip like I said I use a one inch needle so as long as it's getting in the muscle you are g2g