Sylvia,
My thought was to prepare the extension at home and then put it in a little plastic baggie or something so it's ready to go if you need it.
My insurance doesn't cover catheters so I use mine for a week and wash them up after each use being very careful not to touch the insides of the sink. It might be a little trickier to wash with the extension hose on it but it may be worth a try. If your insurance covers the catheters, then you could just make up a few to carry in your purse or something and then toss them after use.
Skirts and nylons??? Well, I'm a pretty secure guy and all but I'm still not going to test out ideas with skirts and nylons!
That would probably be the times that if somebody looked at me funny I'd look right back and say "Yeah, and if you lose your bladder to bladder cancer you'd be able to stand and go to! See how nice my skirt looks since I don't have sit on that darn toilet?"
Mike