I learned this a long time ago from smoking other pipes. When you feel like your pipe is about to go out, cover the bowl with a couple of fingers and then give a few deep draws quickly in a row and you should be able to continue smoking with out tamping and relighting. I instinctively do it and if it doesn't light up right away it probably means I need to dump some ash, scrape the sides of the bowl tamp lightly and relight.