Mashable: But it is only available to YouTube Premium users.

YouTube's queueing system is currently in beta for iOS and Android devices. The feature has been around for a while on the web and occasionally appears in the YouTube apps, but now YouTube Premium users who opt into the test will be able to add videos to a stack that acts like a fleeting playlist.

Upon activating the feature, a "Play last in queue" option will emerge in the video thumbnail's three-dot menu. If you don't have any videos playing, tapping this button will start a new queue at the bottom of your current queue.

When one video finishes playing, the app will automatically begin playing the next one until the queue is empty. Change the order of the videos in the queue or delete them entirely. Your queue will be discarded if you close the player in any way, including by exiting the app or touching the "x" on the player's bottom bar.

According to 9to5Google, YouTube began rolling out the functionality earlier this month. In the event that you did not see this prompt but are a Premium subscriber, you can enable it by tapping your profile photo in the upper right, going to Settings > Try new features, scrolling to "Queue," and tapping the "Try it out" option.

This menu suggests that you have until January 28 to take the evaluation. The feature isn't quite finished yet, as I discovered when I tried to add another film to the queue immediately after the first one failed to be added.

The feature might be handy for some serious binge-watchers who like to watch things on queue, but it's more fun on the desktop, and the fact that it's made it to the YouTube Premium testbed hints that YouTube might be considering it for a future mass roll-out.