Wherever there's less nerves and the toughest part of the meat. My educated guess would be outer lateral calf area. Be carful I pinned my bicep with 23g 1 inch(1.2ml test) dead center highest peek. Sucker got red and irritated. Won't to do that again lol. Still trained throughout the pain.I'm thinking of IM injections in the calves with a slin pin, good idea or bad idea? And where exactly should I pin? Medial head or lateral head of gastrocnemius?