Mahou Shoujo Ai

Both are dark, horror hentai with mahou-shoujo involving tentacles, violence, gore and even death. Not for those with weak stomach. 

Both Himekishi Lilia and Sexy Magical Girl Ai share a lot of similar elements. For one, if you're a fan of the intense and extreme tentacle rape action in either of the two, you're going to like aspects of the other. Both contain tentacles that have instances of poking/stretching visible on the girls outsides. Certainly not for everyone, but for those who enjoy their extreme hentai they'll get a kick out of this as it's not too common to see in hentai, yet. On top of this the same animators who worked on Ai worked with Lilia, so you expect similar designs and styles. Overall, Ai has more of a "nice" ending with more elements of action and magic, while Lilia is more of a big sexual adventure for those with various fetishes not found in a lot of hentai, inflation, huge penetrations (giant monster), petite catgirl, and other various things. Those who like their extreme hentai will probably enjoy both. read more 

Crazy Ai started in 2003. I've been into tentacle hentai since before then and so I've seen it all as the years go by and I have to say at this point, even though I worship Inyouchuu above all, I think Ai and Asagi are comparable when it comes to the "intensity". Both come off as rather serious and with dark tones and the sex can be downright brutal at times. Ai set the standard for making stomach bulging / large insertions a tad bit more mainstream (thank you! ^_^), and did a bit with ahegao, both styles are definitely something you see in Asagi and a lot of newer monster/tentacle releases. If you really want to take it to the limits with tentacle intensity then these two are perfect. Topped off with amazing budgets, still some of the best looking h-anime out there by a long shot.  read more 

If you want some good tentacle based hentai that isn't totally predictable, both Sexy Magical Girl Ai and Inma Seiden are highly recommended. They share a lot of elements with the school girls theme, lots of magic and fantasy, all topped off with plots that are actually pretty interesting. Another great thing is both series are longer than your normal hentai titles, Ai hits 5 episodes with Seiden reaching 6. Chances are if you've seen Ai first and didn't mind the extreme tentacle scenes you probably won't have an issue with Seiden's sexual content, it's pretty hardcore but not Ai-hardcore. Inma Seiden is a definite classic and I'm sure Ai will be considered one in the near future! read more