For science I just pulled up a few long-established pornography-specific subreddits (photo, video, and prose-based) in the current version of RedReader, the app which has been spared the axe by Reddit for now. I can confirm that the NSFW subreddits and individual posts still seems to be working and viewable in that app.
EDIT: Disregard, per reply comments this won't work after an update. :-P
You might need to tweak your account settings. Go into Reddit on desktop and there's a switch somewhere to the effect of "I'm over 18, show NSFW content."
There's an update that makes you login again. It installed for me yesterday. After the update get an annoying locked post from u/redditmaturecontent telling you to go to Reddit access NSFW content now.