Animated sex scenes are nothing new, and they’re not confined to hentai. Even seemingly innocuous anime can come out of nowhere with a surprising hookup. Like any medium, anime tries to cover the breadth and depth of human experience. That, of course, includes sex.
That being said, some of these sex scenes are seriously weird. On the one hand there’s your average lovemaking scene, and on the other there’s toothbrush sex, overenthusiastic hamsters, people having actual orgasms from delicious food, possessed horses, and more. It's a very full hand.
Anime isn’t the only genre that’s rife with off-the-wall sex scenes, video games and comic books have their fair share, too. There's just something about anime sex scenes that can get especially weird. Also, if the description didn’t tip you off (somehow), all of the videos you’ll see below are NSFW. Possibly NSFAnywhere.
This is just one of several Shimoneta scenes in which Student Council President Anna Nishikinomiya leaps onto her beloved Tanukichi Okuma. There's no nice way to put this, but she rapes him. Frequently. In this scene, she covers his eyes with her used underwear, tears his clothes off, and just goes to town despite him begging her to stop.
There are witnesses, but the whole thing is played for laughs, and the only reason anyone seems disturbed is that Anna was supposed to be so innocent, not the whole "no consent" thing. Anime morality is horrifying sometimes.
Also Rankedsee more on Shimoneta: A Boring World Where the Concept of Dirty Jokes Doesn't Exist
This Prison School scene starts off with Hana forcing a kiss on Kiyoshi. She’s angry at him, so she wants to take away his “first kiss.” At first, he’s super upset about this, but then he realizes that the kiss is lips only. This gets Kiyoshi thinking Hana doesn’t know what she’s doing, and that he can turn it around on her. What follows is one of the most graphic tongue-lashings in all of anime history. You see inside their mouths, you see the spit, you see the teeth, you see the individual bumps on the tongues... yeah, it’s intense.
Oh, and the whole time, neither of them are wearing underwear, and there’s a water bottle stuck between Kiyoshi’s legs that’s obviously a stand-in for something else that also goes there.
Also Rankedsee more on Prison School
Considering that the majority of Sebastian’s interactions in Black Butler are with the 12-year-old Ciel Phantomhive, seeing him actually have sex is surprising in of itself. In this scene, he’s using the encounter to get information. He sweet-talks his way into a woman named Beast’s bed, and then convinces her to tell him secrets about her father while she's in the throes of orgasm. This is a great example of Sebastian’s more demonic side, but it still comes as a bit of a shock given the overall tone of the series.see more on Black Butler
The Araragi Siblings Have Toothbrush Sex In Nisemonogatari
Most people don’t think that tooth brushing is particularly sexy, and no wonder - it’s the process of scrubbing decaying food out of your mouth skeleton. That doesn’t stop Nisemonogatari’s Karen Araragi from moaning, pressing her legs together, and blushing furiously while her brother brushes her teeth for her. This isn’t just Karen’s kink, however - Koyomi’s inner monologue is all about how good it feels to be “inside her” and how his sister’s moaning makes him feel “weird.” The toothbrush is a proxy for something else, clearly. Just to make sure you "get it," Koyomi cops a feel at the end. Subtext isn't really a strong suit of the show, or anime sex scenes in general.
You can see the full, unedited scene here.