Play your videos while doing other things such as chating, surfing internet or whatever you want with YouTube playing on background. It hasn't been designed to watch YouTube videos but to listen to them so rotation or fullscreen are useless and they won't work.
9Apps 4.9
![국세청 홈택스 [손택스] on 9Apps](https://go.getnew.app/sg/res/jpg/f7/df/69cc2f90120ec331db2630e0f5b6-6dh.jpg?x-oss-process=style/jmq200)
