https://www.dlsite.com/maniax/work/=/product_id/RJ159024.html/

Base +20, sertg356t34 +6, ADIN0 +6

pt1 here:

/g/2801236/0fc64f6b44/

translated from dlsite:

- Son-in-law's plan to seduce his pregnant mother-in-law -

Ikuko, the mother-in-law who was targeted by her son-in-law, Ryohito, could not refuse their relationship and had a lot of encounters.
A mature female seeks younger sex rather than a withered marital relationship, becomes dependent on it, and becomes absorbed in it.

And his invitation coincides with mis mature mother's dangerous day, and his hot semen is poured out mercilessly... The
mature woman is made to be a mother again, pretending to be her husband and making her womb heavier.

Dangerous day being targeted, period
not coming, mother- in-law's pregnancy,
mother and daughter giving birth...

Base +7, ADIN0 +6