Sounds more like a combination of pitch and yaw:
"I trimmed the aircraft to fly in a kind of sidelong skid: nose high and with the tail swung around slightly to the right"
He skidded the airplane. He applied rudder trim so that the tail was not directly behind the aircraft. He also mentions trying to be nose high.
What this would look like I think. Slow down to increase angle of attack in level flight. The nose is now high (likely already occurred after flameout and ejection attempts without thinking about it - check). Go full deflection rudder trim to skid the aircraft. Now trim the ailerons and elevators to fly level based on drag and adverse yaw. Get out.
Imagine if a car had a setting for every input equivalent of setting speed via cruise control - this is what trimming is.
A car equivalent would be applying the handbrake and "trimming" it so it sticks with your hands off, then steering into a skid so you're drifting, then trimming the steering wheel; now your car is moving in an otherwise dynamically unstable configuration (drifting), but it maintains the configuration hands-free because you have locked-in the settings. A driver could then step out of a moving vehicle without the risk of being run over by their own car