That reminds me of my first night in the hospital after hip surgery. I would have sworn the nurse I had that night was Shultz (from Hogan Hero's) twin sister. She came in sometime in the middle of the night asking had I passed any water with this look in her eyes that I knew exactly what was her plan of action. I immediately told her to bring me water (two pitchers). It wasn't long before I was able to produce something to keep her hands off me. Talking about a scare. I don't know what I was more scared of.... the catheter or the nurse that was going to put it in. 

Ride Safe,
Fired00d

Ok, the following may fall in to the TMI category, but what the hell.
Early in grad school for a while I was dating a girl that was an RN grad student in the nursing department (or biomedical sciences or whatever the hell academic department it was that nurses got degreed out of). For awhile she was complaining that they couldn't get volunteers to be catheterized to show students how to do it. She explained that the volunteer got like 20 bucks or some other small amount and stood behind a wall with just the important bits sticking through to avoid embarassment to both the volunteer and the class.
I didn't know any better. So I figured it'd be fun to be the anonymous willy behind the wall and whisper stupid stuff to her while she was in front of the class and no one else would be able to hear. Trouble was there wasn't any wall. And I still didn't have enough sense to keep my mouth shut. She got a little flustered during the whole demonstration. "Hope and poke" was the only accurate description of what she ended up demonstrating that day. I peed red for a week.