This isn't the first time we've heard of this feature. In fact, Instant Tethering was a feature that began rolling out about three weeks ago on Pixel devices. The way this feature works is the following: Bluetooth is used to talk between two of your Google devices. If a Nexus or Pixel tablet finds itself without a Wi-Fi connection, it can ask your connected Nexus or Pixel smartphone to flick on its mobile hotspot; all is done with a single tap, and there is no need to take out your smartphone. Google's Omri Amarilio went to the Pixel User community on Google's product forums to outline how...
Source: http://www.gsmarena.com/instant_tethering_feature_now_rolling_out_to_pixel_and_nexus_devices-news-23348.php
