How do I keep my bagpipe from slipping?

If you experience problems with a pipe that slips down your side while you play, there may any of several problems at work.  Most of these have to do with how the bagpipe and you (and it) fit together.

Some of these areas can be a problems:

1. too large a pipe bag (can't get arm around),
2. a bag shape that doesn't fit your arm (your arm should not be forcing the bag downward),
3. a blowstick that is too long (again, a position thing),
4. a poorly tied in leather bag (drones forcing the bag into an impossible position),
5. a very loose bag cover (the bag slips within it's cover and falls while you hold the cover in place!),
6. material (clothing or bag cover) that is too slick or (velvet is the worst, corduroy is the best),
7. too much jacket in the armpit (especially if you're fine without the jacket!).  

I have found that the top three are by far, the most common issues.  Your arm, in its natural playing position, should gently "cup" the bag against your body.  Different bags fit better with different people.  Blowsticks often are too long and, when they are, they force the bag into an "unholdable" position. 

The solutions to these problems are pretty clear, but may require some experimentation to really identify the cause.  A mirror or a on-looking, knowledgeable piper can help a lot.

Some players/bands use non-slip Dycem between the bag cover and the body to help out.  Others use scraps of leather - (I had one for a while that said L&M on it!).  Velcro doesn't work as it is too sticky. Don't bother trying to use 400 grit black "sandpaper" glued on the bag as you'll ruin your shirts and it doesn't work anyway!.

My slipping problems were all resolved with a shorter blowstick and a bag that fit me more comfortably.  I can now play in any attire and never have a problem.  I currently play a very heavy setup with a Ross Dessicant system.  Even with this heavy pipe, I haven't needed any "aids" since resolving the bag fit and blowstick issues.   As a point of reference for you, at 5'11" and 165 lbs., I play an extended small Ross bag with a blowstick that is only 9" (tip to bottom of projecting mount).