If it's sticking or chattering it's most likely a build uo of dust and/or grit. The hest thing you can do with the one you have is to use alcohol and a cloth to clean the rod. If you can do so I would also recommend cleaning the inside surface of the slide itself. Just pull it off the end of the rod and use a QTip and alcohol.

Now, if you really would like a better option then replace it with a Teflon model such as that made by Simms or a couple other companies. And take this to the bank; if it isn't white then it's not Teflon. Teflon will have less of a tendency to chatter if and when it gets wet. AGAIN, occasionally clean the rod with alcohol.

Any kind of lube will just gum it up and attract more grit that casues some of the problems you are now having.