First and foremost, an important warning: pepper sprays are severe irritants which may cause serious injury on whomever or whatever it is sprayed on. Keep in mind these are not toys and are dangerous to handle, and as such are best left for responsible adults.

I have kept a pepper spray on my outdoors kit for the eventuality of a wild animal attack or self-defense. The can is large but can fit most pockets, yet still it is not the most practical to draw quickly.

I then bought a Smith and Wesson can in a small format and I loved the case that came with it. So I created a parametric version. 

Fitting the exact can diameter is hard depending on the printer, so I put some grooves inside to get it some slack.

For the cord eyelet, you may need to file it a bit to make it fit in the case. I recommend glueing it with epoxy resin, or a cyanoacrylate glue and baking soda mix.

I printed it with both PLA and PETG and they worked out great but I believe most rigid materials should be fine.

The .stl file has dimensions that fit my three different cans, with an inner diameter of 36mm.