Sounds like the tobacco is packed too loosely. I made this video a while back about the breath smoking technique and a couple of times in the video I stop sipping the pipe for a minute or more, and it remains lit. The pipe in the video can almost always last me nearly two hours.But if I take too long between sips, it will invariable go out.
This sounds like a technique to produce both a hot and wet smoke! It would for me even with a dry burley like Semois. Consider also that the slower smoke renders more flavours and more Vitamin N absorption. But perhaps you don't want those? I must say after 40 yrs of that technique you must have a tungsten tongue ::Wine I sip. Tobacco I puff, though not maniacally. In my 40+ years of smoking a pipe, have never gotten into the go slow and sip approach. I like to see the results of my effort literally. Smoke rising like a thunderhead out of my bowl. :D That probably explains why I could never understand how folks can claim to get an hour's smoke out of a bowl of any size. Even with my largest bowled pipe, I wouldn't be able to get more than 20-25 minutes of smoking out of it.
Not all, you've just found what works for you.I think I may be a bit of a pipe heretic as it seems that I smoke in ways that occasionally run counter to common dictates without ill effect.