New Pipe Smoker With A Question? Ask an Old Fart

Hello gents. I just picked up a newbie Briar on a vacation trip to Monterey last week. I fumbled through a few bowls over the weekend and found that I like the pipe but I need to buy stock in matches. I've read one of the major FAQ's and it mentioned tamping the bowl while smoking. So I have a couple questions about the mid smoking tamp.

1. Is this only done if/when the bowl goes out? Or should it be done carefully even if the bowl is still burning?

2. How does one know when to perform this mid smoke tamping? I did notice an ash lattice work develop in my bowl so I'm assuming sometime around then =)

3. What's the purpose? It would seem the light ash would plug up the works if tamped but maybe it would help to keep the bowl lit more often.

I was even contemplating taking my cigar cutter and whacking one of my cigars into "plugs" to drop into the pipe. Any thoughts? I know it sounds kind of silly when you have a perfectly fine cigar but I think I like smoking from a pipe better.

Thanks for the help!
Chris