Quick copy from the rules.
3. Rated Teen/Mature:"Don't get anyone fired."Â All content on our forums and wiki should fall somewhere between a Teen and Mature rating, or between a PG-13 and a "low" R rating. While your content can get a little racy or violent, don't post anything that would cause a reader to get fired or trigger a web filter. Use common sense to decide what's appropriate and be sure to use the spoiler tag to mark sections "NSFW" (not safe for work) if you have any concerns.
So basically, if it looks NSFW, I'd spoiler tag to be on the safe side.
3. Rated Teen/Mature:"Don't get anyone fired."Â All content on our forums and wiki should fall somewhere between a Teen and Mature rating, or between a PG-13 and a "low" R rating. While your content can get a little racy or violent, don't post anything that would cause a reader to get fired or trigger a web filter. Use common sense to decide what's appropriate and be sure to use the spoiler tag to mark sections "NSFW" (not safe for work) if you have any concerns.
So basically, if it looks NSFW, I'd spoiler tag to be on the safe side.