For Bi's you flex your bi and find a spot in the center of your peak...keep an eye on that sport then rest your arm on a table or desk and keep it relaxed, find the spot on your arm you found and stick the pin in, aspirate and inject. Pull the pin out and flex your bi (it feel good) Same thing with Tri's, find the head of the tri, relax and inject. www.elitefitness.com/members/2thick/ has pics