https://www.dlsite.com/girls/work/=/product_id/RJ01293583.html

[Synopsis]

Ryo, who was kissed by a kind devil and turned into a woman, returns to his original form when his childhood friend Touji gives him a creampie sex but after three days he turns into a woman again.
The rule is that he turns into a woman every three days.
Ryo has sex with Touji every time.
By doing this, Ryo changes little by little without even realizing it.
After repeating this 100 times, he turns completely into a woman--!?

Part 1 (Raw): https://e-hentai.org/g/3018594/5e57f85766/

Base +25, nuts987 +13