No worries! I made a more thorough guide. I broke it down a little more clearly. You may need to click the picture so you can see the full thing.  

Providers: If you post nudes or underwear pictures (anything but fully clothes) you should have "Mark media you tweet as containing material that may be sensitive" checked. If you don't and you tweet nudes or racy pictures you risk being shadowbanned and not being able to reach anyone. If you don't ever tweet that stuff you can leave it unchecked.  

Clients: If you don't tweet or retweet racy material then you don't need to have that checked. But you can if you want to be sure.