Plane "hovers" vertically in place, rotating left around its roll axis.
Plane set-up:
Full 3D throws in elevator and rudder are a must. An aft CG helps a little also. Some flyers will run their CG back to make this maneuver easier without gyros. But gyros provide the best aid to stabilize the aircraft- they won't do the maneuver for you, but they'll help. The pros will also tell you to add 3/4 degree of upthrust to your engine. This helps keep your plane from falling forward in the Torque Roll, and it'll fly straighter uplines in non-3D maneuvers, too.
With a little aft CG, gyros and upthrust, you'll find your plane will be set-up best so you can concentrate on attitude recognition. Naturally, you'll need lots of power for this one: Generally 2 to 1 thrust/weight ratio. That will let you immediately pull out of a bad spot.
How to do it:
Fly low along the ground at low throttle, and gently add power with up elevator to bring the plane into a vertical position. Some flyers add a little left aileron to get the roll motion started. Add throttle to keep the nose pointed up and make corrections with rudder and elevator to keep things straight.
Trickiest part:
Recognizing your correction when the plane's belly is toward you. (Tip: Think push the rudder toward the low wing when the belly is toward you.) You have to be fast with throttle corrections. Most flyers add "bursts" of power, along with rudder/elevator corrections. If you simply hold full throttle, you'll climb out of the maneuver.
Recovery:
Fly out at full throttle.
Worst way to mess up:
Get turned around when the belly is facing you. Remember to push the tail the way you want it to go (when belly is facing you)
