What it means is I borrow X number of shares while the price is at .02 a share and sell them all, with the promise to pay them back in Y number of days/weeks.
During that time, I am charged interest on the money advanced, and have to secure the shares with a "Hold" on money in my account. This hold money can be up to $2.50 a share.
If the pps goes down, I buy back the shares, plus the interest and return them to the Lender, keeping the difference.
If the pps goes up, I buy back the shares, plus the interest and return them to the Lender, paying any overage out of pocket.
I do NOT like shorting. To me its like playing Russian Roulette.