Reminds me of a story in one of J Douglas Harvey's books...
A young lad aircrewman was introduced to the mess early in his flying career, and in his enthusiasm to impress his elder fellows, he over-indulged.
He was encouraged to vent his digestive tract in the bathroom, where a comrade encouraged him: "Keep puking it up until you see a brown ring, lad. Then, pick that up and swallow it again. It's your arsehole."