I was on a cruise for a buddy's bachelor party. We were all hanging out in one suite to unwind after a long night of drinking/gambling/partying. For some reason, one my friends starts trying to grapple with me. I was at that tired drunk level and was in no mood to to even jokingly mess around. In no uncertain terms, I told him to stop...multiple times. Each time resorted to me simply shoving him off and tell him to stop. He finally hit the next level by picking me up with his shoulder and slamming me against the wall. I had some jiu-jitsu training at this point in my life and my arm and his neck were already positioned for an easy guillotine. A combination of being drunk and the shock of him actually slamming me against the wall resulted in me pulling much harder than I meant to. I didn't even feel a tap...his body just went limp. Laid him down and he was just snoring. He came to a few seconds later and I regret what I did and it was definitely not intentional, but he got what he deserved and got fair warning.