I have a few bottles like this and had the same problem. I got empty 1/6 oz. roll-on bottles on eBay for cheap and use an eyedropper to put the liquid in that, and use the roll-on decant to apply it. You don't have to worry about spilling it, contaminating it with skin oil or foreign substances and is just overall easier than using the original bottle.
here's the page of the eBay seller I got mine from: