When I am out and about, I often use my BB9 stem with the Tempest head. To store safely and minimize smell, I use the solution depected: home-made Tempest-BB9 case from pvc. I'd recommend painting one end cap a special color to remind you to only open that end up. As you can see, my cap is black, so I always hold that end up. You can easily customize the length of your storage tube. This is not 100% smell proof, but to my nose, it hides the dankness rather well.
Make sure you have cooled your Tempest before sliding in the pvc. Usually about 60 seconds is enough time for that to happen.
To reduce smell even more, I store all my "smellies" in that Stashlogix carry pack. That small one is for when I must be away from home, but I have a larger bag, also from Stashlogix, that I use for glass and miscellaneous equipment that is prone to smell. Their zippers hold out better than cheaper "smell-proof" bags.
**Edit: some of the Stashlogix bags/purses come with a lock. The one time my lock malfunctioned, the Stashlogix people fixed the problem right away (replaced the product).