A Community Guideline
"Not safe for work" (NSFW) is short-hand on pnut.io for mature content of any sort.
We do not have set rules for NSFW content, but one thing to keep in mind is that minors are likely on the network, and while countries recognize different responsibilities towards them, please have a mind for them when choosing how to post.
NSFW is currently opt-in.
Developers may implement filters with preferences in clients, with settings like "hide all NSFW", "hide all NSFW from non-following users", etc.
Some clients give the option to mark a post as NSFW with a button in the posting dialog.
#nsfw tag in your post will mark it as NSFW except if programmatically marked to the contrary.
Under https://pnut.io/account, you can set your account to automatically mark your future posts as NSFW. This is likely overly sensitive, but you can make that judgement.