The current manner of handling multitasking while on a call is not exactly the most convenient one on Android smartphones. Tapping the back button during an ongoing call means that the only way to get back to the dialer is to drag down the notifications tray, find your ongoing call notification and then tap on it to conference and so on.
The frustrating bit is finding the call notification, which is why most of us would simply tap on Recents and find the phone (or dialer) app and then resume to make a change with an ongoing call.
Google knows Android call management is a problem and it is trying to address it in a way, which would be less taxing than the current procedure which involves the two methods mentioned above.
9to5Google have managed to enable an experimental feature in version 11 of the Phone app, which is the default dialer app for Google's Nexus and Pixel devices. If you hit the back button during a call, your dialer screen will now be minimised to a floating bubble.
The bubble will snap to the left or the right sides depending on where you drag it and will float above any app that is current running on screen, similar to the Facebook Messenger Chat Heads.
Tapping on the in-call floating button, will see the circular icon expand to reveal toggles for a speakerphone, muting and hanging up.
The floating button is not exactly a new feature. BlackBerry has been using the same on its recent KeyONE smartphone as well. It's handy and can be moved around while you work on other apps opening files for reference during a call.
Hopefully, this new feature makes it to the next firmware update or to Android O. For now it seems more like a feature that would arrive on Google's very own Pixel range of devices as opposed to every Android device out there. But let's hope that Google brings it to all Android devices in a future update.