stash away vs stash behind

Some examples from the web:

• I saw him stash away a chocolate bar in his bag.
• I'll stash away the foreign currencies.
• However, at the outset we should say that budgetisation would mean that we would no longer stash away hundreds of millions of euro, as has happened under the EDF - money meant for countries which for various reasons were not efficient spenders.
• Innovation is certainly not promoted as long as multinationals with gilt-edged balance sheets are able to stash away the best part of research and development funds in their accounts, while those who are actually targeted for this kind of benefit are left out in the rain.
• If a lot of stuff is piled up together, then you can easily stash away something for your personal gain.
• It's your money, stash it away.
• For years he went on how he'd got this huge stash hidden away.
• And stash it away from the coal
• They stash it back away into its frozen shrine for another eternity.
• And you're sure you don't want to stash it away somewhere and then I find it - accidentally, of course - months from now, and I get all weird and insecure about why you didn't show it to me sooner?
• Dekker ran away without his emergency stash.
• I jacked a little going-away present from Ric's girlfriend's stash.
• About a secret stash on some uninhabited moon, where you've been putting away loot from all your jobs.
• And stay away from the stash of red velvet cupcakes I have hidden under my bed in the bunk room.
• We saw a guy running away from the apartment and we saw him stash a bag in the alley after you guys went in.

Some examples from the web:

• I stash it behind me, then we burrow through the dirt like a couple of moles.
• And if you get thirsty, I got a secret stash of Orange Crush behind the fridge.