I remember finding out a long time ago when Mustard was streaming. He said the Russians found it out originally, and now I am going to tell you. (Much easier on PS4 btw), simply hold down the left analog stick with your right hand thumb, then double tap the "up" button on the d-pad with your thumb from your left hand. Boom. You are now able to IA Teleport with Impostor. I am not sure how to do it on X1 since I don't currently own one, but yeah, just use the analog stick AND the d-pad, and you should be good to go.