https://www.dlsite.com/girls/work/=/product_id/RJ01225130.html

Prequel: https://e-hentai.org/g/2774946/42b8d4ed72/

[Synopsis]

After a period of training as a bitch, the main character, Hinako (Kuro), becomes the lover of her beloved.
Hinako feels happy with her lovey-dovey days with her unexpectedly kind and sweet lover, Kenji but sometimes she remembers the time when she was kept as a bitch.
Once her body knows the joy of being a dog, it can never go back to the way it was...
Hinako wants to be trained again but she doesn't want to lose her current happiness.
Hinako hides her true feelings and is overwhelmed with the heat of her body but an incident breaks out when a junior colleague at work comes to her for advice.
Kenji, jealous of Hinako's intimacy with another man, takes action...

Base +25, aminoko +6, nuts987 +13