The Righty Tighty is a trickshot that can be done in Call of Duty: Modern Warfare 2 and Call of Duty: Modern Warfare 3. It involves the players' left gun in a sprinting motion and the right gun upright whilst the player isn't sprinting. The right gun is still fully usable but the trickshot is cancelled out if the player sprints or climbs onto objects.
To do this trickshot, you need to sprint forward and backward whilst reloading. It can be difficult at first but once you get the hang of it, it is easy.