I use a small ziptie and tighten it up under the button to keep it from getting pressed and releasing the gas while they are in my bag. So far it's worked for years without coming off (I have a few in various bags).
I also keep some gorilla tap wrapped around them. It's surprisingly handy.
WTB: multiautomatic ghost gun with a .30-caliber clip to disperse with 30 bullets within half a second. Must include shoulder thing that goes up.
Memberships/Affiliations: CERT, ARRL ARES, NRA Patron Member, HRC, CGN/CGSSA, Cal-FFL