Just so there's an official statement here, there are no plans to ban snuff stories. But, in all honesty, they are probably not going to win you any friends. It has been debated over and over (and does not bear repeating) why we took the stand we have on minors. But that's about as far as we wish to go on banning topics.
That being said, I would strongly suggest not doing it. Trust me, you're not going to feel good about it. I went through this whole thing years ago. As someone else here stated, I didn't want to write a tickle-snuff story because I was in any way into it, but wanted to challenge myself as a writer. I went back and forth with Morandilas at MTJ and he gave me valuable insight on the subject. I went ahead and wrote the story...
...and I'm the only one who has ever seen it. I read it back to myself several times and was somewhat shocked that I was capable of writing it. Truth be told, I got the "challenge" bug out of my system very quickly. I have yet to wish to revisit it.
In my story "Sympathy for the Devil", I touched upon the subject, but in a very different context. It was about a dominatrix-type who wound up in Hell because she was just plain evil...and in the beginning of the story had killed one of her playthings by tickling him to death. It wasn't described in detail, and was basically a two sentence blurb explaining why this woman deserved her place in Hell. The rest of the story had nothing to do with death. The point is, if we start banning things like this, the story would never have been written because of the brief mention that was nothing more than character set-up.
Use your best judgement, people. Like I've said about a number of other topics, we often spend so much time wondering if we can, that we don't stop and think if we should.
