How do i know if the white discharge after intercourse is a vaginal secretion or something else?

Hmmmm: White discharge after intercourse, can, of course, be semen if he ejaculated inside the vagina. Otherwise, it's normal to have some whitish discharge that actually comes from the vagina. If your discharge isn't bothering you when you're not having sex, it's likely nothing to worry about. Concerning discharge: it itches, it smells fishy, or it's so much that it soaks your underwear.