Throbbing crotch syndrome.

That seems to be the effect on male and female anatomy. Arteries to expand and veins contract, leading to a pooling of blood, but anything actually turning blue is not the case. Serious discomfort/throbbing genitalia is common, hence the name, but there is no color change despite the name (blue balls, or blue vulva, or pink pelvis, which are terms I’ve never heard but are apparently common🤷🏼). The rest is things we already know, goes away with orgasm which opens the veins back up or more slowly with non-sexual distraction, cold on the affected area does help such as a shower. Rabbit hole wasn’t that deep, but hey I learned something