This glitch is one of those pointless ones, and will be pretty much impossible to do without a friend's cooperation.
You have to do this on a gamemode that lets you get back up after you've been downed, such as King of the Hill. It's also recommended that you set the bleedout timer to 30 or 60 seconds.
First you're going to need a shield. Plant this shield somewhere and stand infront of it so you are able to kick it over. Have your friend smack you in the back of the head twice, and right before he hits you the second time, press the X button to kick the shield over while you are being knocked down. If done right it will look like your body is pointing down into the ground, but just keep tapping A and moving the thumbstick. On other people's screens they will see you moving, and once your bleedout timer expires, you will warp to where ever you managed to crawl to on their screens.
This one doesn't seem to work as host.