As soon as your cm turns back creamy summer and you feel your cervix is lower and firmer you know ov is done. Just dtd another couple of days when it does come down. Just record when you get ewcm. So you have an idea of when ov has happened. I temp and use opks to give me a firmer chart. Bare in mind you could have ewcm or fertile mucus for a few days.

Watery mucus is also fertile. But not creamy.
Savage to put it bluntly you have to check for your cervix with your fingers. In unfertile times your cervix will be easy to reach and feels like the tip of your nose. Test that out before looking for your cervix! When you go in to your fertile period your cervix rises, becomes soft and you will feel an opening on your fingertip, round or oval shape. When it is up high your fingers fully inserted will have trouble touching your cervix. When you are not fertile about half of your finger inserted will then make contact with your cervix. ALWAYS make sure your hands and nails are clean (and short)! Obvious maybe but many dont! I dont even have oral sex during fertile time because of bacteria in saliva that can kill sperm. Sad I know but when you have been trying as long as I have and lost as many as I have you get a little clinical LOL!
So when your cervix is high...get doing the deed till it isnt! xxx