I recently got an frn Dragonfly in a trade. Not sure how old or new the knife is (though it's in great shape) but it also was fairly stiff. I ran warm tap water over the pivot, opening and closing the knife repeatedly for like 5 minutes. Then I carefully dried it and gave it a good blast of WD-40. Then I wiped that off, and hit the pivot with a drop of Rem Oil. Now it's smooth as silk. Like you, I'm loving this little cutter.
My wife and I just bought a new apartment and are in the process of moving. Last night, while hanging curtain rods, I used the knife to open the packages that contained the mounting hardware. They're made of some really thick, tough plastic, but the D'fly zipped right through it. Sweet.