Euphoria

If the main protagonist doesn't have sex with the female cast, they'll all die, well in Jutaijima is only the girls who'll die, but it's basically the same concept, by different ways and reasons, but same concept after all, coincidentally both are adapting a visual novel by their respective names and both adapt different routes, only that in Jutaijima the alternative route is the sequel. Lots of smut with sexy girls in both mainly students and a sensei, you know the deal. 

Both OVA series are some of the few hentai anime that can have the guro tag, extreme roleplay on both, plus there's some occult aspects thrown in the story. Ail Maniax is more hardcore, though. 

Both are adaptations of visual novels about a guy that must have sex with the female cast, all from school, in order to survive, in Euphoria it's thanks to a macabre game like in Saw and Jutaijima involves a mortal virus which makes the girls crave semen or else they'll die, there's technically deaths in both, but in Jutaijima isn't shown anything since it's not the point of interest, it's more of the harem vanilla type, but both are recommended. 

the first part of Boku no Kanojo ga Majimesugiru Sho-bitch na Ken OVA is literally the copy of the white room of Euphoria, and to exit the room you have to complete a challenge like in Euphoria 

Both anime have a lot of violence Both have a great plot Both are anime adaptations of Hentai VN's (Visual Novels) Both are known for being "too disturbing" Both have disturbing rapey scenes (which is one of the reasons why both shows are known for being disturbing) 

At first glance there doesn't seem to be any likeness between Higurashi No Naku Koro Ni and , well a hentai, maybe that both have torture scenes and death involved, but obviously Euphoria is made for different purposes than Higurashi (as kinks), no, the similar aspect between the two comes from the fact that both have basically the same format, that is adapting a visual novel, but animate various different routes that in the original game where only accessible if you replayed it and choose different options, the story progresses until it comes to an end, to later in the next episode or the next scene, go back to a certain point in time and watch a different route, to know an alternative aspect of the story. read more 

[18+] both follow a guy who is happy seeing other in pain except one is psychopatic killer and the other is H sadist. 

Bondage game and Euphoria are both, very dark and twisted tales of BDSM, torture and death. Neither is for the faint of heart. You just might be traumatized.  

Bondage, Rape , Pain, Sexual Pleasure  

They both have a lot of bondage and neither one is for the weak hearted. If you like rough, bloody, kinky sex then you will enjoy both of these shows. 

Umineko and euphoria both have very complex stories that leave you with a serious sense of WTF? Umineko may not be as ahem, sexual as euphoria but they both have their share of violence and gore. The atmosphere of both is also similar. Additionally both are based on excellent VNs that are superior to the animated works but are still rewarding to watch. Finally the main female lead of both is visually identical and acts much in the same way. I've seen euphoria several times and think that anyone who enjoyed one will like the other. Beware vanilla scrubs may be put off. 

The mc has a good reasoning to be put into a situation like this filled with sec and violence and sexual violence... As you watch through the series you see one episode going over another in a contest to be the worst episode ever. And as you finish the series you realize it wasn't worth it to learn about these "weird sex torture scenes" 

if you're looking for some hardcore stuff, like dark, makes you question your sanity, has a large shock factor and some plot, material then both are extremely similar. one can say that these are akin to sexual torture. sure, you could be pointed out to other anime that have tentacles but neither of these use those cliches, they present situations that are impressively far worse. not for the faint of heart