Tips for having sex while ovulating? TMI

I have PCOS and very irregular periods. Only recently have I been taking care of my body and tracking. Last period was july 9th for 5 days. I'm getting sharp cramping pains and I think I may be in my fertile window. Last month when I was ovulating (I didnt know, i get periods about 1-2 times a year) BD hurt to the point I had to ask him to stop. Do I just push through? Or are there positions that might help? The cramping gets really bad

TMI: My SOs d**k is super big so could that be it?