Oopcest is when two consenting individuals of a reasonable age for each other have sex and then later learn that their parents are romantically involved and getting married. When their relationship began, it was not incestual, but once their parents are married, it is oopcest.
It is very common in anime and manga romance.
It is very common in anime and manga romance.
"Rui and Tsukiko had sex. It was fine. Then their parents got married. That's some serious oopcest!"
by BlatentlyFakeAlias January 22, 2021