However, I have also noted with regularity that ejaculation can cause an immediate onset of the firm and flaccid condition, even when it wasn't present prior to the event. Repeated ejaculation
in a short time frame magnifies this.
6. The ejaculation
mechanism releases noradrenaline locally to trigger orgasm, and is the reason why a man goes flaccid immediately after sex. This hormone causes smooth muscle contraction and vascular resistance.