I often build wiring harnesses and use a lot of heat shrink. I started by just having a heat gun at my workbench. (It's messy, don't judge).
One day I was at Hobby Lobby and saw a small "Heat Embosser". It was only $9, so I bought it to try to use it for heat shrink. It worked well, and is just warm enough to melt solder on a pcb. I was throwing things away and found that I had this flexible boom that came from an old magnifying glass that I'd gotten from Harbor Freight long ago. I thought they'd go together better than peanut butter and chocolate!
The items I used were:
Foot Pedal Switch
Step 1: Instructions
The instructions are pretty simple.
The first step was to find a way to attach the heat gun to the boom. The embosser had a handle, so I removed it, providing a great mounting point.
The flex shaft had threads on the end, but they weren't quite the right size to fit the shaft properly.
I did what any respectable craftsman would do, and pulled out the epoxy. I had some of the harder epoxy that's easy to mold, so I filled in the gaps to attach the embosser to the end. It's not a beautiful solution, but effective.
I also had an old foot pedal switch that I could use to make the whole operation hands free. The pedal I had was one that just plugs in between the item you want to control and the wall socket, so it was easy to install. You could get by without the pedal and just the switch that's on the heat embosser, but only a savage would do that.
Use a few zip ties to clean up the cables and you're done! You have a heat gun that you can bend to the position you want and operate with your foot.