#tip Individuals can block entire instances. Just pick an individual from the instance in question, go to their profile, and open up the menu you would use to mute, block, or report them. Under these options is another one: hide all posts from <instance>. You'll be asked to confirm, just in case. Once you pull the trigger, refresh your feed. You won't see material from the instance you just blocked.
I just verified this by blocking switter.at, BTW.
Don't get me wrong: I'm glad Switter exists because sex workers need and deserve safe spaces more than anybody else, but I visit Mastodon on my phone at my day job instead of going out for a smoke break. I don't need un-tagged NSFW material showing up in my feed.
And I don't mean nudity. Because I'm a man, a woman looking over my shoulder and seeing a photo of a woman in lingerie can accuse me of sexual harassment. I don't need that hassle.
@SoniEx2 Being able to automatically mark all media from an instance as sensitive would be nice, but in the meantime you can use the method I described.