In my younger days, I did it that way in a '70 Torino Cobra and '69 Mustang GT, both cars equipeed with toploaders.
Lay on the ground with the
trans next to you. Roll over and hug the
trans. Roll onto your back, bringing the
trans with you. Bench press the
trans onto the guide pins, and slide it into place. Then take a break and let your blood pressure drop back to normal.
I'm an Old Guy now, and wouldn't even consider doing it that way. I wouldn't recommend it to anyone else, either. Now I let my tools do all the hard work for me. Work smarter, not harder.