To keep this simple, let's assume I am using a wallet like Bitcoin Wallet by Bitcoin Wallet developers on an Android smartphone. I go into a coffee shop and buy using my bitcoin wallet. I understand that it is going to take about 5 to 10 minutes before the transaction is first registered on the Blockchain.
How can I then "double spend" my bitcoin?
You just can't. Satoshi Nakomoto took care of this. You may try though, but there were no successful double-spend in the whole history of
BTC as far as I know.
and several double spends have happened when sellers gave the goods before at least 2 confs