So you could say I'm one of the better BJJ guys out of the people that I train with (not that that actually says a LOT or anything, since I train with lots of guys who do this only on their free time at my university). Anyway, today I was training MMA with a friend of mine with a strong background in Gojin Ryu karate. He is a tough kid and he is a nice guy. But whenever we spar, it seems like he always goes 100% and tries to seriously knock me the f*** out. I always try to maintain my control, especially since I do outweight him by 30 lbs, and I don't really want to bang it out hard with him. So we are sparring and I take him down, and I start throwing some punches to his side/ribs. He proceeds to punch me pretty good in the back of my neck. I feel a tingle and I'm like damn, okay, I gotta be more defensive, this guy is ROUGH. then he elbows the back of my head, and I really feel it this time. So I got upset and I started raining some punches down on him and I look clearly angry. I told him if he was going to elbow me or hit the back of my head, I would too. Then he asked, "I'm assuming that these [motions a knee from bottom guard to my head] is illegal too right?" I'm pretty much dumbfounded since I thought we were sparring and not trying to kill each other. Anyway, did I have a right to get angry and get "violent" as he put it and rain down punches after he elbowed the back of my head?