Attaching a torch/flashlight to your BCD so you can use it but not drop it.

[JossRincon]

Get a retractor, especially if you are talking about a smallish light. Some things that would have used a couple C-cell batteries. I keep one like that in a BC pocket with the retractor clipped to a d-ring inside the pocket.

This! Got a simple, inexpensive retractor and clipped it to my BCD - made life way more simple.

 

[Belzelbub]

Several options, much will depend on your set up.

My BC has a pocket with a D-Ring nearby. So, I have a bolt snap with a small section of line attached to the light. Light goes in the pocket, line is small enough to fit under the zipper when the pocket is closed. I attach the bolt snap to the D ring, put the flashlight in the pocket and zip it closed. It's out of the way and secure. I can actually operate the light without removing the bolt snap from the D ring. But if I were to use for a more extended use, then unhooking the bolt snap would be needed.

 

[Eric802]

For a quick peek, you may be able to leave it clipped to the chest D-ring. For longer, a hairband or bungee on your wrist:

View attachment 836859

I've done it exactly like this with the hairband while snorkeling or if my computer is on my left wrist.

 

[Chavodel8en]

The Goodman soft mount at DGX is $10. DGX Soft Handmount