Not your's®

It seems like you're interested in a YouTube video description that includes the phrase "Not yours_ff" or something similar. However, the text you provided is very short and a little unclear.
"Not yours_ff" could mean a few things:
 * A specific tag or hashtag used by a content creator, perhaps related to Free Fire (FF), a popular mobile game.
 * A common phrase used in the YouTube community related to content not being owned by the uploader (e.g., re-uploads, compilations, or fan edits).
 * A specific title or part of a description of a video you saw.
To help you find what you're looking for, could you tell me more about it?
 * Are you looking for a specific video?
 * Are you trying to write a description for a video of your own?
 * Did you see this in the comments section or the description of a video?