I am just starting with airbrushing, but the first thing i noticed was that the gun would not fit my hand in any comfortable way. 2 hours and 4 prototypes later this is what i came up with.
It fits one of the cheap china made airbrush guns like a glove and can be easily removed for cleaning.

Edit: I added asecond file for people with even larger hands, as it turned out the first one was still to small for me.