Just out of curiosity, I read the doujinshi. If you're looking for hardcore graphic sex-wise, why don't you just show that one to your friend, I do agree that it's pretty extreme 🤣 .
OR
Maybe hentai + yaoi in the genre search will help you?
Other doujinshis out there are pretty graphic too, I mean, I haven't really seen that much extremeness (like the one I saw in the doujin you linked) in yaoi sex if you're talking about original stories...
OR
That is, if we're talking hardcore sex-wise...if you want "disturbing" like in your title, VampireBanana's suggestions or some weird combination like pedophile + yaoi would work.

[url]http://www.mangaupdates.com/series.html?id=507[/url]

It's called Hoshi no Yakata

It is quite possibly the most disturbing yaoi manga I have ever read.

Don't know why I forgot to mention this, but Moyashimon dj - Kitto Kawaii Otokonoko dakara is pretty good for what you're looking for. It's practically hentai.

Love Prism and Mob for Jack are pretty hardcore too, I'm actually surprise nobody has mentioned any of them yet so you should take a look ^^

Oh yeah! I just remember this manga called "Hawaiin Hearts II"...I know you are looking for hardcore sex scenes and this is not really strong at all, but it definitely takes the cake with the "disturbing" part! Trust me watching obese guys having sex is DISTURBING XDDD

"I exist, that is all, and I find it nauseating" -Sartre

Lord of the Ring. I wouldn't say this is necessarily 'disturbing' but it made me feel rather uncomfortable for some reason.

And if you're looking for a yaoi with pretty boys than forgot the manga I just mentioned. 🤣

I would recommend In the Womb as well but it's shota (and shota as you can possibly get). It's not disturbing (or maybe it is to some) just plain crazy.

*Beavis: "Wait, what's pornography?"
Butt-head: "Uhh.. I think that's like, the study of porn." *

Quote from Yenoh

Just out of curiosity, I read the doujinshi. If you're looking for hardcore graphic sex-wise, why don't you just show that one to your friend, I do agree that it's pretty extreme 🤣 .
OR
Maybe hentai + yaoi in the genre search will help you?
Other doujinshis out there are pretty graphic too, I mean, I haven't really seen that much extremeness (like the one I saw in the doujin you linked) in yaoi sex if you're talking about original stories...
OR
That is, if we're talking hardcore sex-wise...if you want "disturbing" like in your title, VampireBanana's suggestions or some weird combination like pedophile + yaoi would work.

well, now you understand why I said its worse than... being raped by a horse... in manga...

Update on my Search: Looking through one of my favorite manga site's yaoi section that has some of the most extreme stuff I have ever read... and I found something by the same mangaka who drew the gravitation dj, because I saw they had the same drawing style, thinking that nothing could be more hardcore then the dj I read.... and I found it. Something more gross than that gravitation dj. Not only does it have alot of SUPER GRAPHIC SEX, this time it also includes

• vampires
• guns
• guts
• intestines
• a priest
• much more...
  "OH GOD NO." you say.

LINK. I DONT KNOW WHY IM INCLUDING THIS BUT I HAVE WARNED YOU. DO NOT CLICK ON THIS LINK IF YOU ARE ONE OF THOSE PEOPLE THAT DONT READ POSTS, JUST CLICK ON THE LINKS. THIS IS WORSE THAN THE GRAVOTATION DJ.

http://manga.animea.net/kanpai-dj-unapai.html

btw, I read Hoshi no Yakata... the kanpai! doujinshi is way worse...

and Lord of the Ring... I thought it was halarious but it was pretty... gross... and... wierd...
someone even wrote a haiku to describe it;

 read at your own risk  

nipples and exploding butts
male tentacle porn

Eh. It is NOT disturbing at all... Lol I've seen things a million times more disturbing T.T

The most disturbing, well it is a yaoi but it focuses on the main killing people then all these little boys follow him and he explains how they touch each other sexually and try to kill each other.

i think it was called "Black sun child" 🤨

🤢 it is really disturbing.
Oh and there was another i forgot the name but this preist kills vampires but he fucks one of them but he can only climax when he blows their guts out 😛 which he does but the vampire ressurects its a one-shot but its okay i suppose. 😉

I want to go far, far... faraway-- beyond the city~

Do you want disturbing sex scenes or disturbing story?

MURAKAMI Maki (村上真紀) writes the most graphic yaoi I've ever read. There was a scene in the Gamerz Heaven! dj that made me want to throw up.

As for disturbing story lines: Saezuru Tori wa Habatakanai and Double Mints have some pretty traumatic moments. They're also very smart and beautiful in a messed up way. O_o

ETA: ah, it's an old thread '^^
well, the recommendations are still valid.

Super old topic, but... Bokki-Zu is probably the worst yaoi manga I have ever read.