I was aged about 21 at the time and met a boy in a nightclub. We flirted all night then I took him back to my place for some fun.
First he was so drunk he could barely get hard. When he did eventually manage to get it up, he just pumped away for ages while I lay there bored. He finally finished (without even attempting to satisfy me) and I fell asleep.
When I woke the next morning he was gone, and so was all my money, my credit cards, my jewellery and various other trinkets from my home. Before I had time to take it all in, the police were knocking on my door. Turns out he'd left in a taxi from my address and then mugged the taxi driver on the way home too.
The police could barely keep a straight face as I sheepishly gave my statement and then made me go down to the police station to look at mug shots.
...worst shag ever....