Swiping has become ingrained in our collective muscle memory for touchscreen navigation, and now YouTube's adding it as the mechanism for getting to the previous or next video in the Up Next list.
Swipe left and it returns you to the video you were just watching; swipe right and it sends you to the first video in the Up Next list.
Since that list changes with every video, it's amazing how much faster you can get sucked into the black hole of random videos with some mindless swiping. Just seven took me from CNET's Lexy Savvides in an exoskeleton to "Dental Mental: Classic Mr. Bean."
Right now it's only available with the iOS YouTube app. I asked about Android, but didn't immediately hear back.