both of the series are really similar in following ways.
the male lead character is that type who always need resolve a misunderstanding and always is forced around nobody listens to him(most of time) and he is always looked on as a pervert (he is not) ,as always mc like this are always thought of m by the female characters. the male characters are so similar that you almost can find differences in them. like both of the characters have imoutos who have something to do with "sex".both have nee chan who are not blood related and makes sex jokes both have rich girls who like to make misunderstandings .both have anime mothers who talk a lot about sex and their daughters are prodigies.both have a teacher who talk about sex freely(all though setokai yakuindomo has the best perverted sensei ever). both anime contains a lot of dick jokes bdsm jokes and japanese wordplays the only difference between them is that takatoshi is single and haruka isn't (all the girls kind of love takatoshi though.