SETTING YOUR CHANNEL ON YOUTUBE TO "NOT CHILD FRIENDLY"
In your browser go to: https://studio.youtube.com/ If using your phone or tablet set it to "desktop version". Click "Settings". Next click "Advanced Settings". Click on No (middle option) to be set to not child friendly. Click on Yes (top option) to be set to child friendly. Third option you have to mark each video one at a time as child friendly or not. If you do not YouTube will decide for you. There is a possibility of getting a rather large fine and losing your channel if they think you are marketing to children and it's not child safe.