Your friend is correct if you sell any of your bitcoins. Any bitcoins you sell/trade for $$$ you are suppose to report/pay when filing your taxes.  If not you do run the risk of getting caught and being audited.

No one likes to pay taxes but you probably should even if you feel like its a small amount and the IRS would never notice, the last thing you want is to be audited, being audited can literally destroy your life and cause so many headaches.  Better to just pay your taxes on any money you make from selling bitcoins.