Sharing android screen with friends can be very useful when you need some help or you want to share something while doing on your phone.
You can do shopping together while doing a chat over video or voice and watching a single android screen.
Recently a new app launched on product hunt: light beam which lets you do all of these things in few taps
Play Store: https://play.google.com/store/apps/details?id=com.lightbeam.app
App Store: https://itunes.apple.com/gb/app/lightbeam-screen-sharing/id1441056479
Motto: Make any app collaborative with lightbeam’s social screen sharing.
After downloading the app just open and signup
Invite your friends with whom you want to share screen
When added, just tap on the friends and start sharing screen with the option to voice & video chat
There are many more apps for screen sharing available in play store:
Team Viewer: https://play.google.com/store/apps/details?id=com.teamviewer.teamviewer.market.mobile
Inkwire Screen Sharing: https://play.google.com/store/apps/details?id=com.koushikdutta.inkwire
Which one are you using?