Yuzuru Hagino isn't just a girl - she's a slave. Her "master" is Kai Renge, a sadistic womanizer who enjoys playing with his "honeys" - students who have their expenses paid in full at Houjou Academy in exchange for helping their masters graduate - and then throwing them away. All Yuzuru wants is to excel at her studies, but she must also fend off Kai's wandering hands and dodge his onslaught of degrading insults at the same time. With master/honey basketball games and competitor masters out to steal her away, Yuzuru will do whatever it takes to impress her master and graduate the Academy.
Yori Yuki has loved his twin sister ever since he can remember. While his parents brushed it off as a child’s fantasy, he always knew it was true love; but because it is incest, taboo, a forbidden love, he did his best to eliminate those feelings. 15 years have gone by and his feelings never wavered; in fact, they have grown stronger. He’s watched his sister Iku grow up and become a beautiful woman, and now, he can no longer contain his feelings – Yori confesses. Yet even if Iku reciprocates his feelings, that doesn’t change the fact that they’re brother and sister. Can forbidden love last?
The main similarity is that both series have relationships that you wouldn't expect to work. You will find that in both anime there is someone in the relationship that is jealous and somewhat controlling. Oh, and the way the characters are designed is really similar too.
The male figures in each Honey x honey Drops and Boky wa Imouto ni Koi wo Suru are controlling. The theme of forbidden love is in each anime series while the characters overcome that in very unique ways.
Kotoko Aihara has always been in love with Naoki Irie; he’s tall, handsome, and rumored to be the most intelligent student in Japan – who wouldn’t be? Only one thing stands in the way of a relationship with Irie: Kotoko is ditzy and is at the bottom set of her school, and Irie-kun hates nothing more than ditzy, stupid girls. When disaster strikes and Kotoko is forced to move in with Irie-kun’s family, she suddenly sees her chance to bridge the gap. After all, even cool, super-intelligent guys must have a soft spot, right?
Itazura na Kiss also features a guy who is a jerk but who eventually cares for the female lead. Honey x Honey Drops is more on the dramatic side, while Itazura na Kiss is more of a romantic comedy.
Hazuho's at it again! Mizuho's voluptuous mother is back, and she's making trouble again, putting the moves on hapless Kei. How serious is she? Serious enough to take him to a "love hotel"! How will Mizuho take it? How will Ichigo and Herikawa react? And what other couple is getting hot and heavy?