Your friends can now easily cast videos to your Chromecast thanks to a new feature called guest mode. The new mode allows anyone in the room with an Android device to jump on your Chromecast — even if they're not connected to your Wi-Fi network. Enabling guest mode on your Chromecast is just a few taps away.
How to enable guest mode in the Chromecast app:
- Tap Devices, select your Chromecast.
- Tap Guest mode.
- Slide guest mode to On.
That's all there is to it! Guest mode is available to anyone running Android 4.3 or higher (no support for iOS).
Source: Google Chrome Blog