Having a tough time hiding paper is one of the reasons BTC is popular. I'm not sure how redundant the answer "Safety Deposit Box" is, but I'll leave it here regardless.

You can leave it in the shoe-box where you hide your drugs.
You can laminate it and stick it in your sock, carrying it with you everywhere you go.
You can wear a cup and stick it in there.
You can stash it inside an old-computer case.
You can stick it down the barrel of an out-of-commission firearm and retrieving it with pipe-cleaner(s)/dis-assembly.
Under an old floor-board, inside a picture-frame, behind the actual picture.
Stick it over the batteries, but inside the battery-case on your game-boy.
Laminate it, dip it in wax repeatedly until it forms a Candle-shape and then stick it in a box.
It's a piece of paper, and you literally could put it anywhere.

You can think of your own unique place, because the best things are self-taught, self-suggested and self-maintained.