Best enteral feeding tubes & pumps according to redditors

You're looking for surgical tubing.
Here's an example of some: http://www.amazon.com/Grafco-Latex-Tubing-Wall-50ft/dp/B003T437BI.
Its made of natural latex rubber and is incredibly resilient. Latex is cheaper than silicon and just as practical in this particular instance. That's a 50' roll, that's why it's so expensive. But you can buy it by the foot at any Home Depot or Lowes for very cheap.
The tubing will fit nicely over the glass straw of the ash catcher. And you can attach it to the bong using something like this: http://www.badassglass.com/14mm-to-14mm-adapter.html from your local head shop.
The adapter there is a male to male 14mm adapter. If possible you should get one that goes to 10mm as its much smaller and you'll be able to easily slide the tubing over it. Send me a picture of your bong when you get a chance just to see what we're working with.

It looks like an extension set though it looks different from the continuous feeding ones we use in the hospital. A quick amazon search shows it may be a “bolus feeding extension set”. There are several types to look through. Here’s one

Even easier some small-diameter surgical tubing like this.

Wow, those Water Weenies look pathetic. We used to make our own, it's just surgical tubing that you can find at any medical supply store. Just tie off one end, for the other end use the top part of a twist apart pen as the nozzle. You can make them very long this way and I think they are thicker too.

Your dentist will tell you no, but if you can figure out a way to push air through your devices airhole(s), you can just put your lips over the drip tip and push the vapor in that way. You would just have to inhale instead of suck.

You could also run some tubing from your device to a gravity bong and use that if you are so inclined. Or make some fancy work with tube and a balloon. Who knows.