Follow below instruction -
- type m.youtube.com in your address bar. instead of www
- search for your video and click on video link.and from the window right click on watch video (or image) and select copy link address.
- use quicktime player(works on vlc but the sound may not work so use quicktime player) and from file-open url. and paste the url that copied from video (just press ctrl+v). and hit okay your video will be played.