Maglite made for the 2xAA a mouthpiece I haven’t seen that for 18650.
There are universal headbands for 18650 with a rubber loop.
I would go with an L-Shaped light. You can clip that to your jacket front pocket.
And they come often with a headstrap, which I seldom use. Clipping in front of my clothes is often enough.
Thanks! the shrink tubing idea made me think of going to Home Depot. They have the spools of flexible plastic tubing by the foot. I wonder if the ID of one of those would work!
Oh, and the shrink tubing makes me wonder about putting it in your mouth for a while…. what chemicals are in there that get it to shrink / is it food safe?
Of all the holes in your body your mouth should be the last one used to hold a flashlight. If you used an angled light you might be able to use, no that’s no good either. Don’t put it in any of your holes.