One of the best ways for watch video with your friend is Google+ Hangout. While watching videos you are also able to chat with your friend and group. You can use Hangout for watching YouTube videos also with your friend while chat. Below you can find few steps to help you to watch YouTube video with your friend with Google+ Hangout:

1. Click Start a Hangout from the stream.
2. Add the circles or people you want to alert that you’re hanging out.
3. Click the YouTube Icon on Bottom left side, to start YouTube Video Sharing.
4. You are ready to watch your favorite YouTube with your friends; you can also search the YouTube video there. Anyone in the hangout can play, pause, or change a video.

Please be informed that to cut down on echo, everyone is muted by default while the YouTube player is open. You can click the Push to Talk button underneath the video to talk.
The volume control of the YouTube player is specific to each person.

Link: http://www.google.com/tools/dlpage/res/talkvideo/hangouts/

Enjoy!

Tags | google plus, Social, Social Network, Video, youtube