Tehcinally, your friend is correct. You don't need to take the sugar pills at the end of your pack (i think they're green) If you skip the sugar pills, and go DRIECTLY to a new pack of hormonal pills, thats call 'skipping your period' if you don't give your body that hormonal withdrawls, you shouldn't get your period. HOWEVER, since ortho-tri-cyclen is a higher dose pill with changing hormone levels each week, many women do not skip their period successfully. And will end up having 'break through bleeding' a week after they skip their period. and break through bleeding tends to last a lot longer than a regular period.
You can also simply just not take the sugar pills. They don't contain any hormones, so you can simply throw them out. They're actually in your pack of pills to keep you on schedule. since you're ONLY supposed to have a hormone free week for 7 days. So, instead of swallowing your sugar pill, you can just throw it out. But make sure you don't get off track and forget to start your active hormone pills again in your next pack, or you risk pregnancy.