No, because newground does server side checks based on your IP. I did try to force search adult content but the server doesn't return it if you can't access it.

The add-on will only works with the websites it's built for. Trying it on another website will do nothing. You can check on the extension's description, as well as the wiki (there's a link in the extension) for which sites are supported.

For newgrounds, try a VPN or to access it via Tor?