I've had these "Travel John" gel packs for a while, and I gotta say they come in really handy. When you're up there for 3 hours at a time and you're keeping hydrated, well, you know. These things are really neat. Some people might be grossed out by it, but I dig it. You piss in it, and whatever chemical is in there swells up like a fat warm gel sponge. No spills. When you're done, just toss it in your flight bag or whatever and you can throw it away when you get home. This is the saving grace for me on long flights.
It was a lot easier to use in the Mooney, where you could just slide the seat all the way back and kind of elevate yourself in the seat a bit, but in the RV it's a little more precarious...but obviously doable!