Yes, you would need to be on the pill for this to work. I'm not sure how it works on a multi-phase pill (such as Ortho Tri Cyclen) but on pills where every pill is the same except for the last week, all you have to do is skip those last pills and go on to your next pack. The last week of pills is when you have your period, so without them, you can skip it. Some people experience spotting while doing this, but I never have and it works fine for me when on vacation or during an event. I just don't do it often.