I love this one! There's a story of how a man told a snake that if he made it rain then the father would give his blessing to marry his daughter. The thing is that he made it actually rain. But once the snake came to the girl she told him to be with his grand son instead.
And that's just the start of the story ;)
ch 9.2 - holy fuck those sex scenes were hot af! The best ones I read in a manga!
Kamisama no Uroko