NSFW sites still contain valid UX patterns, so shouldn't be off-limits for suggestions. However we obviously need to tread carefully.
If you're concerned about someone accidentally clicking an unsuitable link then I would suggest keeping the link as plain-text and prefixing it with NSFW, so the user can copy the link text itself and not accidentally click it from work. Something like:
Have a look at this site (Caution, NSFW): www.example.com
(This might be a bit overkill though. If you warn the user upfront that it is NSFW then that is likely more than enough. As a moderator I probably wouldn't remove a link presented with enough of a warning upfront (unless the target link is incredibly unsuitable).
Remember, that an answer should still exist as an answer in its own right, and not require the viewer to go off to another site to find what they're after. So you should include description and screenshots (edited for suitability, obviously) to illustrate your answer, and then provide the link only as an example or citation.