how to make more sticky desoldering tool? 
i often fail when desoldering switch 
I was taught a desoldering trick by a lady who does production soldering her whole career and relayed to me by my current professor. I'm studying industrial electronics and this was in a class on professional fabrication.
What you do is cut/melt a small "mousehole" notch right on the tip of your soldapullt, if you hold the soldapullt vertical it'll look like a little cartoon mouse door or something on the end/side of the tip.
Now you can place the soldapullt directly over the pin you want to desolder and still get the iron into the correct spot to melt the solder, WITHOUT having to try to melt it and then rapidly position the soldapullt as normal. That tricky timing part is completely eliminated with her "mousehole" method and the soldapullt still makes plenty of suction to clear the joint.
I sacrificed a tip (they are cheap) to try it out and it works wonders for my desoldering abilities. Before I was sometimes too slow to move the pump into position and hit the button before the solder rehardened. Now I get it right every time because the soldapullt is already in the perfect position before I even melt the solder

Again there is still plenty of suction to completely clear the joint. (Some may think it won't "seal" right, but it is never really "sealed" against the board anyway.)
This has sped up my workflow and made the process much easier. I can post a pic if it doesn't make sense, but it's really simple, just put a notch on the tip that lets me put the iron tip in from the side.