I had some trouble finding this option. My first instinct was to click the settings button on the left, but that's where it is!
First, you'll click the name of your blog on the left sidebar to bring it up on your browser.
Then click "Blog settings" on the right sidebar once your blog is brought up. That's where they're hiding it.
Click "Prevent Third-Party Sharing" under the Visibility section, and bam! You're done.
Thankfully it's much easier on mobile. Just click the Gear icon on your blog's page, to go to settings.
Scroll all the way down until you see Visibility, then toggle the Prevent third-party sharing option for your blog!!
If you disable this setting on mobile, it automatically synced it to my web browser settings, too. ...But if you use both Web and Mobile, I would still highly recommend double checking that it actually turned off on both!!
Check that it's turned off on your side blogs too! And check your settings every now and then anyway to ensure that it's staying turned off, because if my memory serves right, some other websites will pull some shenanigans on things like this and opt you back in without telling you!
Leave Feedback on New Features at Tumblr Support Here!! Let Staff know however we can that having our content fed to AI at their whim is unacceptable.
And if you have the option to poison your art with Nightshade or Glaze, keep it up!!
AND AND IT HAS 10K+ WORDS AND IS STILL BEING UPDATED?!?
New political strategy just dropped.
Taiwanese parliament member stole a Bill before it could get passed. 
@NFL Someone sign this man as a running back.
“ummmmm ur bra strap is showing :/ ”
the nuisance of our language is stunning
Here's some notes on some of the upper body muscles so you, artist, don't need to look them up
They are not medically accurate, just enough for artists to know the necessary muscles and how they work together
I 100% recommend doing the last exercise I did to be able to actually place the muscles
So I put this as one of the backgrounds
Yesterday, I found that someone changed my background to something soccer related, so just to mess around with them, I put this
Today, I looked at all the computers around me, plus my computer and
You children…………..
You are playing a dangerous game.
We are not the same.
[SONIC 3. Scene idea. Sketch]
I can see sonic trying to approach with dialogue and sharing his own story with shadow, as if to empathise with him.
But Shadow doesn't care, and even sees incongruities and hypocrisy in his actions, judging Sonic's affection for Longclaw.
"You lost her and did nothing? Did just accept it? No, we're not the same"
To Boop - either tap the boop button next to someone's name or go to their blog and tap the cat paw icon
To Super Boop - go to someone's blog and hold the cat paw icon until it spins once, then let go
To Evil Boop - go to someone's blog and hold the cat paw icon until it spins twice, then let go
Can't Boop - either you or the person you're trying to Boop hasn't opted in yet
To Opt In - go to your feed and you'll see the boop-o-meter and the option to opt in
I'll update this when I know how to get certain badges and such.