I broke the cap on my glue bottle. I remembered this device based on a product called "Twist-n-Seal". But it would take longer to buy than to print - so here is my version. Use your slicer to stretch or shrink (using "scale") to the general size you need - two versions are shown in the photo from the same STL file. I made mine in TPU and the flex filament version works great but I think a solid version would work OK.
UPDATE 1 - If you print in flex filament like TPU then I suggest 100% fill - not for compression strength but for tensile strength - My original glue stopper broke after multiple pulls out of the container (it was only 30% fill).
tapered_stopper_small.stl | 162.4KB |