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When I was a teenager a friend's dad (a doctor) told us how, in his student days, a Nigerian sailor had come to St Thomas' Hospital with his todger trapped in a short length of gas pipe. He'd left it too long and the part poking out of the pipe was gangrenous. Only amputation would save his life. When he came round and was told what had happened, he was "very angry" apparently. It's still there, pipe and all, in a jar in a collection, apparently.