Three of my boys were long cutoffs, one by design trying to do Shettles (I think he may have been one attempt too though I can't quite remember) and then the other two, one we weren't even trying and I had sex right after my period had ended when I thought it was safe, and the other, my husband changed his mind about trying and we stopped long before O happened, I was sure I had NO chance that month either. The 4th boy was a sneak attack, IDK when I got him, but we were having regular unprotected sex all the time so it would have been very unlikely it was only on O Day!