Sipping your pipe is a gentle pull letting the smoke pool in your mouth slowly and pulling a little harder on occasion to keep the pipe lit. Puffing is a series of more rapid, harder pulls on the pipe creating puffs of smoke like a smoke signal. Sipping results in a cooler smoke, though it can increase humidity. Puffing creates a hotter, drier smoke, but has the problem of exhalation into the stem of the pipe, which creates drool in the pipe if you are not careful. The other thing to mention is aromatics vs. non-aromatics. Aromatic tobaccos are heavily flavored and often burn considerably wetter, so even though the tobaccos "taste" better, i recommend staying away from them until you get your technique down. You can't get much better tobacco than Dunhill so i doubt the tobacco is the issue, and as 05venturer is less than 100 miles from you, I doubt it is the humidity. Try spipping at your pipe more and taking it out of your mouth if you build up too much saliva, you will probably have to relight often. Aside from that, what people were not saying about the Peterson system is that the P-lip is designed for sipping and it's hard to do otherwise, so a Peterson P-lip might help your technique.
Smoke em if you got em!
Erin