I'm not sure this is 100% appropriate for this site since it isn't quite an everyday problem, but here goes.
Let's say that I have this special piece of jewelry that I have to show to the doorman of the secret organization I'm in, in order to enter the hideout. It is a 5×8×1 cm (2×3×0.4 inch) aluminium rectangle with our logo carved into it.
I need to carry it on me (everyday maybe), but, at the same time, nobody must see it. I need to conceal it in such a way that:
It (or clues that might lead to it, like a necklace chain if I were to wear it as a necklace) is completely hidden/hidden in plain sight while I am wearing a regular outfit. For our purpose let's say shirt and jeans. It's perfectly fine if I can't hide it while in my underwear.
I can access it relatively easily and quickly. I don't want any awkward situations with the doorman.
It must be safe - both from pickpockets and accidents (someone bumps into me, I trip and fall etc.)
So how should I go about this?
PS: Both in clothes and in body hiding places work, as long as they abide the three rules.
PPS: No. Having the outline of the object show trough my shirt without any camouflage is not acceptable.