PiPifier is an Action extension for Safari that lets you use every HTML5 (thats about every web video on iOS) video in Picture in Picture mode.
If you have an HTML5 video playing on any website like Youtube just press Run PiPifier in Safari's Share Menu to enable Picture-In-Picture for this video.
With this extension you can even run PiP mode on sites that hide the native video controls (so that you can not enable PiP there)
1. Open Safari
2. Open the Share Menu
3. Choose More
4. Enable 'Run PiPifier'
5. Select 'Run PiPifier' on a website with a video