This post will contain spoilers.
The concept is basically that Yamada is a girl entering high school for the first time, and she decides that she wants to make 100 sex friends (pretty sure that "fuck buddies" is a better translation and that Funimation just tried toning the language down). Fortunately for her, she's quite attractive and there are a number of guys who want to date her. Unfortunately for her, she's still a virgin, and she's also incredibly self-conscious about it. So she resolves that her first time will be with another virgin, and more specifically, one who won't intimidate her. She settles on Takashi Kosuda who is, well...very plain.
In anime, this is about as close to "plain" as you can get.
From there, the story becomes your average "young people with crushes on each other try to express their feelings but keep fucking it up" story, with the gender of the protagonist (most stories like that star males), the upbeat and silly tone of the show, and the fact that the relationship focuses on sex, not love, setting it apart from the average.
Oh, and the show is very much ecchi, which means, for all you who aren't familiar with anime fanspeak, that while it's not outright porn, it does get fairly explicit at times, so the show is definitely NSFW. In fact, the title basically translates to "B Cup H Style," with H being a euphemism for sex. The entire show is packed with fanservice, and the innuendo in the OP alone is thick enough to walk on. Seriously, watch it for yourself.
I love the opening, incidentally. Catch song, entertaining visuals, clever innuendo (to explain the venus flytraps quickly--"venus flytrapping" is apparently a Japanese term for seduction that most western audiences wouldn't pick up on)...I wouldn't call it one of the best, but I do think it's good.
Anyway, the show is definitely entertaining. It's awkward, funny, and sweet. I really liked watching the relationship between Yamada and Kosuda, especially in the beginning. Yamada I've always been a sucker for cute, awkward romances (I"s is one of my favorite manga and that was pretty much the entire plot of it), and it definitely delivers that at first. In addition, because the show doesn't take itself particularly seriously, all the setbacks are funny instead of depressing. Yamada isn't just awkward around Kosuda; she appears to be completely socially inept in general. The audience gets a good look at both Yamada's confusion over how to handle things and Kosuda's complete confusion at her mixed signals. The problem isn't that Yamada's shy--it's often that she's the opposite. She thoughtlessly says or does things that probably shouldn't be said, making her a wonderful example of an Unsympathetic Comedy Protagonist.
The only problem is...things feel like they fall apart more later on in the series. Probably about the same time that Kyouko, a rival for Yamada in terms of looks, is introduced. This is the point where subplots and love triangles that don't go anywhere start popping up. Kosuda's childhood friend, Mayu, has been in love with him for years, and is probably the better choice for him, but she's unable to act on her feelings and he's completely oblivious to them. Kyouka intends to steak Kosuda from Yamada just to spite her in her quest to become "school queen." Of course, Kyouka is in love with her own brother (Oh, Japan!), who is in love with Yamada. None of these relationships go anywhere, and they're just sort of in the background. In addition, Yamada...isn't exactly the most likeable person. She's incredibly selfish (a recurring theme in the series even points this out) and only cares about sex, and Mayu would probably be a better match for Kosuda. However, as the relationships between characters other than Yamada and Kosuda are shoved quietly into a corner, there's not enough incentive to care about anyone other than the protagonists.
And the ending was disappointing. Kosuda's admitted his feelings to Yamada, but Yamada still hasn't admitted hers. While their physical relationship has advanced, their emotional relationship is still heavily lacking, and it leaves a sort of bitter taste in my mouth. Yamada never really moves past caring about sex when the entire point of the show seems to be about her developing a more mature perspective on relationships. On top of that, by the end of the show, the two still haven't even had sex (they've come close a few times, but there have always been interruptions). I'm hoping there's a second season that develops their relationship more, but as it is, the ending rings hollow. Nothing's really changed between the two of them.
And finally, there's the censorship. Oh holy Farore the censorship. I'm regretting not watching the show uncensored. See, in the televised broadcast (and pretty much everywhere that isn't the DVD release), offending material is covered up with boxes reading "Ogre Brand," which seems to be an in-universe brand for condoms, tissues, and other things throughout the series. Unfortunately, the boxes are large, intrusive, and often unnecessary. In later episodes where the censorship is needed most, the boxes show up more frequently, and by the end, I was sick of "Ogre Brand." Now, I'm all for moderate censorship. However, I also think that any censorship should be done tastefully. The "Ogre Brand" boxes were funny at first, but by the end of the series, they're unwieldy, tacky, and obtrusive, and their humorous nature often destroys any mood that's been built up.
Anyway, those are my thoughts. Would I recommend the show? Well, as it is, probably no. If there's a second season, I'll probably watch that and come to an ultimate decision then. If you're going to watch it, though, track down the uncensored version. I can't say how explicit it would be, as I haven't seen it, but I can say that it'd probably be aesthetically superior, as you won't have those clunky boxes covering half the screen.