I can't believe I'm asking this, but I have to know. I've been skipping it all together and just changing out bags, etc, but that's such a waste. How in the world do I use the coupler? Do I cut my professional bags or something? All I do now I just stick the tips into the bags because I can't seem to figure it out. I didn't want to cut my non-disposable bags without knowing if that's how to do it. Thanks for patience with me!

you put the coupler in the bag before you cut it. push the coupler all the way to the tip and it will mark on the bag where it will be cut. remove the coupler and cut the last impression closest to the tip. then re-insert your coupler into the cut bag. the opening should be small enough that the coupler doesnt fall through the cut bag. screw the other piece that comes with the coupler with your tip onto your bag.
i hope this makes sense. whats in my head and how im typing are not meshing. im sure you'll get a bunch of responses -and hopefully much better directions!

right from Wilton -- here's how

http://www.wilton.com/decorating/decorating-basics/using-couplers.cfm

Yes, you would cut your featherweight bag to use your coupler correctly. I suggest you go to Wilton's website and type in using a coupler and it will take you to using your decorating bags and how to use a coupler and there is a video to watch.

Be sure not to cut right at the threads of the coupler. Your bags will stretch over time and use and if you cut right at those threads the coupler will push out and no longer fit in your bag right. I also cut halfway between the threads and the end on all my bags.