Believe it or not, I actually connected two of those little red tubes together. I took a match, heated up the ends of the tubes, and stuck them together. I went through about eight tubes before I got two that still passed gas and didn’t leak. It was a pain. I tried to get three stuck together, but the failure rate is so much higher than the success rate, I gave up. Once I had a working dual tube, trying to make it three just ended up ruining the working dual tube.
Perhaps someone can come up with a better method than heating the ends with a match.