You could put it behind your ear. Hard to lose it, easy to notice when it's missing and everyone around you knows you're getting some later.
Personally, I have little stashes of them all over the place. In the medicine cabinet, bed side table, glove compartment, book bag, wallet and front pocket (when applicable). I've never been a boy scout and I certainly aren't setting any records for *getting some,* but I'm a firm believer in being prepared. In the off chance I luck out and convince/fool a woman into sleeping with me, I don't want to screw that up because of a technicality.