>>24049457My phone as a feature where you can play YouTube even while the screen is turned off but if your phone doesn't have any of that there's a trick you can do in your phone browser.
First you click on a video or stream
Then you click the YouTube home button
Then after that if your phone has an undo or back gesture do that and in a split second before the video has loaded in yet, switch to another tab in your browser group. I know it's confusing and might be hard to follow but it works