NSFW Artwork

First of all: My apologies if this question has been asked before!

I just wanted to know Imzy's policy on NSFW art, more specifically fan art involving fictional characters. The NSFW section in the policy says "no pornographic images" and also "use the NSFW setting if you have nudity and graphic violence or other possibly NSFW images". X-rated fan art of fictional characters is not really either, it's not pornography as in "xxx rated pictures of real people posted for show/spam only" but it's not just nudity either, there is more involved, but in the end it's still ART. (Hence "fan ART".)

I'm not a fan artist myself but I received a wonderful piece of commissioned x-rated fan art last night and I hesitate to post it on my personal blog (using the NSFW option, of course, its clear that it falls under that) because I can't really find specific rules about fan art in the policy.

Help?