I think it would of been funnier if he'd asked " How do you guy's empty your sacks"!
I'm a C5/6, complete motor neurology, and I can empty my legbag. It's something I've learned to do over the years, in fact it took about 3 years before I could do it, but now I can, I am independant throughout the day, and can be left on my own.
I have my legbag situated on my right leg, on the inside of my calf.
I pull up to the toilet, put my brakes on, put my left arm around my pushing handle, and my right elbow on the front right corner of my cushion. I then put my right wrist behind my right calf, and with the leverage I have with my elbow on the cusion, I can use my bicept to lift my leg onto the edge of the toilet.
With my leg on the toilet seat, I can then pull my trouser leg up to get access to my legbag. I then sit up, put my right arm around my right push handle, and use my left thumb to push the tap open on my legbag.
Once emptied, you just reverse the proceedure, and that's it.
It usually takes me about 2-3 minutes from start to finish.
I have often thought about making an instructional video of the procedure, as it's difficult to do unless someone shows you. Maybe a project for a future section of the site.
Simon.