How do you post in a NSFW stream

Do you mean, How do you mark a submission as NSFW ?
When you get to the Edit image page, complete the title and tags
Beneath those, there is a nsfw box that you tick/check.
I hope this helps

No I mean like how do you post in a stream like cursedcomments

Streams marked nsfw

Go to imgflip.com/m/nsfw
Click on follow

Go to imgflip.com/m/cursedcomments
Click on 'follow' on the blue box
This should add 'cursed comments' to your streams
When you've made your meme you should be able to post in that stream

I've always wanted to own a Lego Gaza

Whelp the green screen on the Kyiv one 😭💀