I bleed like a mother in the delts, and it seems the knots take longer to disapate. But, i still do them. Bis are my fave. I have also found my rear delts to be fairly painless in injecting, its a little akward at first though. Turn sideways in the mirror, push your arm down on the sink counter, and find the meatiest part of your rear delt, relax your arm, and inject it.