Wait... are you TTC or TTA?
If you're TTA, then you abstain as soon as you see a hint of CM. Sticky Creamy, whatever. Then, after you've Oed, and your temp has risen for three days, you can stop abstaining.
If you're TTC, then you'd want to have sex every other day or every couple days around your fertile period to give time for dh's sperm to build back up.
In a vacuum, a woman is only fertile for about 48 hours MAX. Usually less than that. That allows for the 24 hour period that the released egg can remain alive. But when you add CF into the mix, you can be fertile for as long as you have fertile CM (before O). The fertile CM provide a hospitable environment for the sperm to live inside of you. So, you may bd, then not ovulate for a couple days, but the sperm are still alive, so they can fertilize the egg when it comes. Does that make sense?
Have you read TCOYF? I highly recommend it. I had read other books of NFP before that, but once I read TCOYF, it all became clear.