Please Twins isn't a sequel to Please Teacher, but rather a spin-off. It's set in the same town with crossovers and cameos from the old series, but all-new protagonists (Maiku, Miina and Karen). You don't need to see Please Teacher before watching this, although I think you'll get more out of it if you do. If nothing else, at least then you won't be thrown by Mizuho's teleporting or the OVA episode bringing together the casts of both shows. I watched them back-to-back and had fun. They go well together. Both are slightly dodgy romantic comedies, except that Please Twins is the more extreme and unpredictable.
Maiku, Miina and Karen were abandoned at birth. Raised independently by foster families, their only clue to their pasts is a photo of two babies (one boy, one girl) in a paddling pool outside a house. When that house was glimpsed in the background of a television news story one day, all three abandoned their lives and headed there in the hope of finding their family. By the end of episode one they've met up and are living together in the actual house, rented by Maiku.
The twist is that the photo only shows two babies. Maiku, Miina and Karen all have the same unusual eye colour, but two are twins while the third is unrelated. When they learn the outsider's identity then that person will have to leave, but until then they've decided not to kick anyone out.
Please Twins is a good show, perhaps stronger than Please Teacher, but it demands more patience from its audience. Despite his best efforts, Maiku becomes the focus of the romantic attention of two classmates (one male, one female) and his two "sisters". That's right. It's another incest anime. Oh, and in case you were getting blase about twincest love triangles, another cast member is taking a more than brotherly interest in his little sister. The list of this show's fetishes is staggering, with sexual attraction riding roughshod over such minor details as inappropriate age differences, gender and being related by blood. You'll also have no idea where it's going. Innocent Westerners might think that even anime heroes wouldn't end up polluting the gene pool with the ultimate taboo, but anyone thinking that clearly hasn't watched enough Koi Kaze. Things get particularly freaky when Miina and Karen start colluding in strange and slightly scary plans.
Like Please Teacher, it's not above wallowing in formula. Stay well away if you hate harem anime, while Miina and Karen occasionally drove me to distraction. You'll want to throw things at them. Hopeless cases, the pair of them, and it doesn't help that they come across as being a good six years younger than their "twin brother". All three are supposedly sixteen, but Maiku is hard-bitten, responsible and mature while the girls can be twittering halfwits. They also look barely twelve years old in their nude scenes... oh, did I mention those? Miina and Karen hold all their serious discussions when bathing together. Please Twins may be more grounded in realism than Please Teacher, not being science fiction, but it has much more fanservice.
However fanservice isn't the reason why Please Twins is one of the most sexually charged anime I've seen. That's the thing about incest... hmmm, now there's a sentence I'd never have written if I hadn't started watching anime. Sex isn't sexy. People on the point of having sex are sexy, which after a while is definitely the case with Miina, Karen and Maiku. As in Koi Kaze, the sexual tension never stops building and eventually the characters are teetering on a knife edge. They want to. They know they shouldn't. But they might not be able to stop themselves.
I shouldn't overstate my case. Like Please Teacher, this is a gentle show aiming for nothing more than romantic comedy with a little bite. I liked the characters even better than their predecessors, most noteworthy being Maiku. The heroes of these wish-fulfilment genres tend to be meek nonentities. Not here. Maiku is blunt, self-possessed and initially downright unlikeable. He has a programming job, rent to pay and no interest in being lumbered with two girls. Eventually he thaws, but that spikiness lends more edge than we're used to in this kind of show.
Everyone's entertaining, but my favourite character was Morino. She's overcome her problems from Please Teacher by becoming benevolently evil, with a Bond villain laugh. Fu fu fu.
Again as with Please Teacher, there's a thirteenth OVA episode in which everyone suddenly has sex on the brain. Well, even more so. I can see why many people hated this, especially given that it throws in the entire Please Teacher cast for no reason whatsoever, but personally I liked it. It rewarded those of us who'd just watched both series back to back and resolved some outstanding issues between Karen and Miika. It felt like it mattered. I liked that.
Please Twins is a good show, but it doesn't make things easy for its audience. It's guaranteed to drive away anyone with no tolerance for silly girls. Maiku's unlikeable in the first two episodes, although that's deliberate. The themes and content are also somewhat startling. I thought it was great, but then again I'm a big soppy bunny.