I don't type /stick on, just /stick and it works...well, sort of, /stick has never worked as well as I would like, but I am pretty sure I just do not have something configured correctly.
My old ghetto movement code (which I got from the original hunter mac before MQ became MQ2) is what I normally use. Oddly enough, after this last expansion, that code is misbehaving in some situations. It's acting as it would with extreme lag, like it can not get an accurate loc of my target in order to calculate the distance.
Anyway, back to your question. Hitting the move back key (whatever you have it mapped to, s for me because I like the wasd movement keys as in fps games) breaks stick. Armysoldier already mentioned it and it has always worked for me. Check your configuration of MQ2MoveUtils to see what you have things set to.
EDIT: Just looked more closely at your post, with all the negatives in your sentences I did not initially get what you were asking. You want to know how to have it always stick, even if you move your characters around? I'm almost 100% sure that stick does not work that way. It seems to be designed to be easily broken and if you think about it, it makes sense. Imagine the problems that could occur if stick could not be quickly stopped...imo having it unstoppable would be really bad.
That being said, sometimes it drives me nuts how easily it stops working (ie fleeing mobs). In my case, I probably do not have something set up correctly. I just put in my own code to move the character near the mob and then had the macro /stick again, with whatever parameters you like (/stick 10, /stick moveback 12, etc.). Check how you have MoveUtils set up.