Timing of sex + first IUI help please

J

Hi everyone ! So excited for our first <a href="https://glowing.com/glow-fertility-program">IUI</a> this month. Wishing you tons of baby dust and prayers!! So I went to doctor yesterday for monitoring - my largest follicle was at 13mm and estrogen had doubled. I go back again tomorrow to see where it’s at. DH and I had sex yesterday... when should we have sex again? Tomorrow AM ? (He is better in mornings). Today and tomorrow ? If tomorrows results find I’m ready for trigger shot I just don’t want it to be too late for natural sex ... any recommendations?