We use this so it's easier to sweep the laser around for pets to chase without having to press the button down.
The ring can be slid into place and twisted counterclockwise over the laser pointer's button and will remain on without holding the button down, and can then be turned back off by twisting the ring clockwise.
Cheap laser pointers aren't really meant to be kept at 100% duty cycle for extended periods, so be aware you can reduce the lifetime by doing this.

All the other obvious disclaimers apply: do not point into anyone's eyes or give to children, especially with this in place.

This pointer's model appears to no longer available but it was named "ThuZW Store USB Rechargeable Green Light Pointer", but there were clearly many different sellers selling the exact same model with different branding.

Print instructions

Needs to be low enough layer height to support the slopes for the overhang, 0.15mm was enough in my tests.