How do I use a stopper-borer?
The idea is that you have to slice, not push. Also these do not work for silicone rubber stoppers, they do work for natural rubber and cork stoppers.

Well, I should say under human power. If you take the handle off the tube end of the borer and put it into a drill, like a bit, and use it that way, you will be able to drill through the silicone bungs.

Important Use lubrication, other wise you won't even get close to making a hole. It would be like trying to go down a slide made of velco while wearing a sweater.