Butt punch

My husband and I smack each other in the butt. A lot. Like a high school boys basketball team. It's like flirty teasing at this point. However, we also do butt punches. Because we're idiotic morons. It's usually gentle. Sometimes with enough force to make the other really grab their behind and whine about it briefly. Tonight, though...was not cool. Yesterday I smacked the hubs, open hand, in the butt. Fairly hard? Yes. He whined about it for a while and told me that he owed me one...and with interest. So as we're walking through Walmart tonight, trying to decide on which of the horrid lines we want to stand in, out of no where he punches me in the butt. Hard. Too hard. I caught the rush of breath that flowed from my mouth to block the bad word that danced at the tip of my tongue just waiting to come out. Then I grabbed my butt. Oh yes, all right up in the front of Walmart. Several, people watching. I have since continued to rub my damaged goods and taunt the hubs about punching his wife in the butt and bruising me. All while he laughs hysterically at my 'dramatized pain.' Psh. It does hurt. I think he hit a muscle and made it start to spasm or something. Intelligence tells me it's time to break the bad habit to prevent any further similar incidences, cut my losses and call a truce. However, revenge burns in my mind. He has no idea what the threat "I owe you one...and with interest" means.