[evolution]

Getting the surgical tubing to stick to itself is extremely difficult. But if you have the flexible insert inside (which is larger in diameter than the inside of the surgical tubing, but by just a little), the surgical tubing should get gooey and fuse with the insert.

It will definitely stink - same thing that happens when you burn the end of bungee cord to keep it from fraying. Now, I don't know if the stuff being produced is toxic. That's something to find out.

That's my understanding based on what my Coach explained with the fused piece he pulled out from some years ago.