-belly punching
-vomiting induced via pain, object in throat, or blunt force trauma to the abdomen (i.e. NOT illness, motion sickness, overeating, or drunkenness)
-mouth/throat torture with sharp objects (think King Crimson vs. Metallica from vento aureo -- basically my wet dream)
-teeth pulling
-force feeding
-live vivisection

basically if it involves pain and/or damage to the upper digestive system i'm into it