It's a pain to try to use a coach's whistle that's on a lanyard around your neck if you're wearing hockey gloves. So I made a holder for the whistle that, along with the strap of your choice, will attach it to your glove.

Two versions, one mounted straight, the other at an angle.

Use TPU or another flexible material.

I had these straps already: https://www.amazon.com/gp/product/B07J4P7WBD. The length of the slots for these straps is 36mm. You can adjust the Y on yours to make the length fit whatever straps you have.

If your strap doesn't have velcro like the one above, you can consider printing out one of @rorys3d's Robust Buckles: https://www.printables.com/model/281536-robust-buckles

Specs for examples in pics:

Zyltech Black TPU (Shore hardness: 95A) .24mm layer height 4 outer walls Inside to Outside wall ordering 5% infill (pattern doesn't matter)

Included 3mf file was used in Cura, not PrusaSlicer. Printing the angled one took 23 minutes on an Ender 3 S1 with a SonicPad.

This is the whistle in the photo: https://www.walmart.com/ip/American-Whistle-Corporation-American-Classic-Whistle-Black/908743265