I prefer quads and glutes, glutes because of the almost complete lack of sensation involved, quads because you can see what you're doing and no twisting! other sites I've tried are biceps, calves, delts which were all fairly uncomfortable, and lats but I hit a vein on my second shot and haven't pinned there again since... I'd love to get comfortable with one more site but just haven't found something thats working for me yet....