Your FTB payments are based on yours & your DP's income for the entire financial year. They calculate based on your estimated earnings what you would be entitled to, then you would be paid in fortnightly payments of the same amount each fortnight, or a lump sum payment at the end of the financial year.
You can ring each fortnight & report your earnings for parenting payment. It would also take into account both your's & your DP's earnings for the fortnight, but if neither of you work for a fortnight you might be entitled to a payment. If you do work you could get nothing, or a reduced amount. I'm not sure if there's a max amount of weeks you can do this though. It might be that if you don't recieve a payment of PP for 12 or 13 weeks then you would go off entitlements to it. I really don't know.
Best to look on the website, or even go in & ask.