I made a post in the Sex section of MN a while ago which, with hindsight, was probably an error of judgment on my part. After posting it, I received a message from a man who initially gave the impression of being sympathetic and understanding regarding the situation I originally posted about. After I responded, he soon tried to steer the conversation in an overtly sexual direction. He claimed to be in possession of a "big spongy helmet" in reference to his penis, while also describing what he wanted to do (or wanted me to do) with the aforementioned appendage. I have seen and heard penises described using various slang and alternative names through the years, but that one probably takes the prize for the least alluring way I've seen one described.
He also sent other messages of a sexual nature. I later looked up his posting history on MN and there seemed to be an insidious nature to it - he has posted in threads from women having difficulties in relationships or posting about sexual issues under the guide of offering support or helpful advice. I assume these posts were made were trying to give the impression of being helpful, when his true intention was to message women with the intention of getting his rocks off and hoping they engage. I was naive and fell for it. I have learned my lesson now however.