Sakura no Himegoto - Ura Yoshiwara Koi Jihen

Sakurako is an office worker who has been chosen by Yusei, the number one person on the lord's list, to be the "Go Handiwork" at a festival in the town of Urayoshihara. She goes to retrieve the cell phone Yusei took from her, but on the contrary, he teaches her how to do it! As she gets to know Yusei, Sakurako begins to develop special feelings for him... What does Sakurako witness when she goes to the Phoenix to see Yusei by herself? Ten million a night, the fourth episode of the forbidden love suspense with the No. 1 flower town is included!

source: https://www.mangaupdates.com/series/xl319vs/sakura-no-himegoto-ura-yoshiwara-koi-jihen