Quoting Safka9973:" I once received the most severe rug burns I have ever had in my life. It was so excruciating I had to ... [snip!] ... I had to bandage it and use Tylenol pm to get to sleep for the next three nights. Never had anything funny happen, though."
At the end of one of my husband's four days during AIT, we had stayed up all night talking to his parents (we had to leave at 3am to make it to the airport in time), so we had no time for sex. I had happened to be driving his brother's car, because he needed our truck for moving. So on our way down, we realized we we're 30 minutes ahead of schedule.
We pulled over on the side of the road and got right to it.
I had severe burns on my right knee afterwards, enough to scar. It was definitely the best sex ever though. LOL.