First I have to say: What a title for a forum thread!!!
Jason, I did what you did - tested on a trainer at home and just let the tube run into an empty milk jug.
It does take a little practice to actually get a "flow" going - in that you have to relax enough to get started, but once you do - well, nuff said!
In reality when actually riding outside, you can pick a nice short downhill run that you are coasting on - and then the relaxation issue while pedaling is pretty much a non-issue.
I also bought whatever sized tubing fits into the end of the catheter, and taped it up so it would not slip. I think it is smaller and more flexible than the connector thingy you usually connect to the it. Then I measured just enough tubing for me to be able to "hold it away from the frame" a few inches. When not used, I just stuff in into my shorts.
I do not now how some people do it (ride for hours and hours and hours) without peeing!
I read in Marco Bahlo's race reports that he only peed one time (1 time!) during his entire 24 hour at Sebring ride in 2015, and I think that was after 23 hours! Amazing - but he is amazing 533 miles on an UPRIGHT in 24 hours!!
I just do not see how you can do it unless you are forcing yourself into at least some sort of minimal dehydration.
Me, it seems like I have to pee at least once an hour, and it I don't it just gets more painful and more painful as I wait. Maybe that means I am drinking too much, not sure.
I think in my Century record attempt last year that I did not go for the entire 4 hours - so that's probably a record for me!