Ovulation Cramping

Been TTC for almost a year. I was being mislead by Glow and the other apps for my fertile window. I started using OPK's to determine when I was actually ovulating and turns out I was ovulating well after the window my apps were predicting. Anyways, when i was getting my first positive OPK of the month I've started to notice the following day I will get bad cramps for a few hours. I'm assuming they are ovulation cramps now that I'm able to see a pattern. Do the cramps occur when your egg is actually being released? Or do they come after the fact? Then about a day later my BBT rises -- I guess I want to know the best time to BD based on the cramping! Anyone??