This may already be common knowledge to the rest of you, but I had to learn it the hard way.

If you put your cell phone in your sporran, don't leave it on vibrate! Talk about a rude awakening!

I was in my office explaining some calculations to a young lady in my engineering department when my sporran started vibrating. She must have thought my crotch was on fire, the way I yelped and started grabbing at it!