Hanagumi Ninkyouden

From Deux:
Aoi Ichimura is a member of the Yakuza family known as the "Flower Gang." He has just been promoted unusually fast for saving the boss’s life. Aoi has a reputation as a rough, tough, ready for action macho man, but in reality he is just a very timid guy with good luck. Now he is assigned to be the apprentice of underboss Yuji Sakiya, who has just been released from prison. Aoi learns to be manly in a different way… trying to be the perfect lover for Sakiya.