I'd never do more than 2cc in one injection. 3cc is way too much for me. Imagine how long the needle would have to stay inside you. Plus the oil would not dissipate well. Just do it in two different injections.
I found when injecting 3cc's into my quads, if I take a heating pad and put the needle in it, let the oil get warm, 3cc's is no big deal and there is no pain or cramping.....