It's filthy enough to have an uncensored version. Hayato Izumi is a stick-in-the-mud who learns in ep.1 that his parents gave him a fiancee when he was very young and never got around to mentioning it. As you do. This fiancee is Ui Wakana, the girl who beat him in the school election for the post of student council president. She did this by:
(a) being sexy
(b) giving an election speech in which she promised to push for the liberation of love
(c) throwing handfuls of condoms into the audience
Ui moves in with Hayato. He's not sure about this. She also likes getting intimate, shows her nipples regularly (in the uncensored version) and is ready to have sex with him. Hayato is even less sure about this and tends to complain about things like waking up with boobs in his face. As you do. Teenage boys, grumbling about every last thing. However Hayato isn't actually made of stone and he's liable to start responding when Ui sticks her tongue in his mouth, shoves his hand down her knickers, etc. It's probably just a matter of time before Ui gets pregnant and their marriage gets formalised in a hurry. They haven't yet had full intercourse, but I'd certainly call them sexually active.
Yes, it's that kind of show. I liked it. The Ui-Hayato relationship is interesting and the filth actually makes it stronger. However it's a fairly silly show with a harem comedy angle that I strongly dislike.
For starters, I like Ui. She's more real than you'd expect. She works out that she's keener on Hayato than he is on her. She's hiding insecurity. She never says anything about Hayato always calling her "president", but then you see her reaction when on one occasion he actually says her name. When the show sets up something hurtful, she doesn't just shrug it off. When she sees Hayato coming out of a love hotel with a girl with huge boobs (they were sheltering from the rain), it's not just a sitcom punchline. She doesn't attack him at all, but instead takes it quite hard and spends all of ep.5 processing it and working out how she should move forward.
Meanwhile I like the gratuitous not-quite-sex scenes because they're saying things about the characters. They show us the weight of Ui's commitment and how hard she's trying. Of course they're basically the money shots in a silly, exploitative story that primarily exists to show animated nudity, but Ui doesn't see them that way. They also undercut Hayato's apparent rejection of Ui and show us how the relationship's moving forward. Hayato might claim not to want Ui hanging around, but that's not how you reject someone's advances (to put it mildly) and he's upset in ep.5 when she moves out for a while.
It's sweet. There's a joyful innocence about it. It's tearing to shreds an anime cliche in which a teenage boy and a girl have to live together with no adult supervision and nothing ever happens, even when they fall in love. Hayato and Ui are all over each other... and this isn't being seen as a problem, but as something healthy and to be celebrated. The show is supporting the characters who want everyone to be free to love, whereas the killjoy point of view is being presented as pathetic.
I admire all that. However the harem stuff breaks the show.
The root problem is that Hayato doesn't want to tell anyone about his relationship with Ui. This causes lots of problems, is insulting to Ui and makes no sense. Why not? Just say that you're boyfriend and girlfriend, or even more simply that you're engaged. It's true! Problem solved. Admittedly the school's disciplinary committee are a bunch of Nazis who hate seeing students even holding hands, but Ui's fighting them anyway. Of course you could argue that Hayato's keeping it all secret because he's in denial, he's scared of commitment, he's not sure if Ui's really for him, etc... but no, the anime doesn't give us any of those answers and instead just avoids the question. In fact there's no reason at all. This is an ecchi harem-ish comedy that wants to throw other girls at Hayato and to hell with story logic.
The effect of this is to make Hayato stupid and a bastard. He's stupid because he's creating a rod for his own back, e.g. claiming to be a cross-dresser just because someone's found a bra and knickers in his flat. What a stupid twat. Stop lying. You're embarrassing yourself and making the audience hate you. Then it makes him a bastard because Misumi for one is falling for him and he's encouraging her misunderstandings with his false pretences. He's hurting people. Those episodes can piss right off.
In fairness, ep.10 half-provides an attempted explanation. "Those kinds of rumours hurt the girl more than the guy." That's true. However that still doesn't explain why he doesn't squash the rumours with the truth, instead of feeding them with risky lies. There's also the more prosaic possibility that Hayato's just being a teenage boy, with no real emotional commitment to Ui and so their sexual activity means nothing beyond the normal, selfish reaction of males to opportunity. However that assumption would make the whole show hateful and distressing, instead of just a few bad episodes, while also Hayato seems better than that to me. He definitely acts on lustful reactions, yes, but a horndog in his position wouldn't have still been a virgin at the end of the series.
The harem nonsense is clearly meant to be as light-hearted and charming as the rest of the show. There's some emotional insight into Misumi, for instance. However the show still includes Misumi's offensive sister, who's practically a rapist, and multiple paedo-appeal characters. One of the latter even gets lots of filth in ep.11. I really hope she's not as young as she looks, although in fairness at least one of them definitely isn't. Ui's mother looks about ten years old, yet she's the show's most dirty-minded character. (That said, though, I liked her. She's channeling her efforts into getting Ui and Hayato together, while her characterisation is an odd combination of childishness and mother hen. If nothing else, you can see where Ui's liberated principles came from.)
It's like watching two shows. The main show is both silly and serious, with a message I wholeheartedly support and a surprisingly meaningful central relationship. It's shoving nipples and knickers in your face (and indeed in Hayato's), but in a way that works. It's fun to watch. However there's also that ugly second show bolted to the main one, like a remora fish underneath a shark. I didn't enjoy those, but fortunately they only damage a few episodes. (You might consider skipping eps.7-8.)
I'll be watching Season 2, though. The good outweighs the bad.