These are my favourite Yaoi Doujinshi's EVER! They're all smutty do, since I like my doujinshi's like that. This is not in order, other then first place, and this list is kinda full with messed up dj's, so not for everyone's taste! (you can find any series I post on mangago)
Haikyuu dj - Hito wa Sore o Shitto to Yobu by Kuroquis & Kuro
This is just HOT AS SHIT! This is my personal favourite out of all these 5, since I love Haikyuu and these are my 2 favourite shippings out of the series. But also because the art is SO good, the smut scenes are PERFECTION, and Kuroo's and Bokuto's faces and hot as shit~ For any Haikyuu lover that wants some smut, THIS is it.
Gamushara Mob Rape 2 Chikan Jigoku Hen - Kuroko no Basuke DJ by Sigmaster & Pureslider
This doujinshi is, not so normal. It's kinda of messed up, since as the title says, it's rape. I personally don't mind yaoi manga rape, cause I'm messed up and have read WAY worse yaoi's, but this is another one that's not so great for anyone out there. If you don't mind rape, bondage and smut, then this is maybe for you.
Shingeki no Kyojin dj - Fan Service - Omegaverse by Tani Rinko and Rodring
I personally think this is the cutest out of all of them, since it's not just the sex but also the feelings. It's still kinda weird and unique, and ofcourse smutty as hell, but if you want a smutty dj's that's not f*cked up crazy, then I would recommend this one since it's on the sweeter side!
NULL NULL - Gintama dj by 3745HOUSE , Tekka G and Takeru Mikami
This dj's was kind of, weird? It just depends on how smutty I want it, sometimes I read this and just think: WTF TenTICALS?! and then other times I just make my creepy ''ohyea~'' face. This should only be read if you want hard smut with tentical action, not for everyone.
Ao no Exorcist dj - Anata Shika Mitasenai by Fizzcode and Satou Nishiki
I personally have read all Ao no Exorcist dj's by Fizzcode and Satou, and love ALL of them, but they're kind of psychological, so it's not everyone's taste. I personally however loved this, and ofcourse all their other dj's of Ao no Exorcist. If you do love some smutty psychological dj's, then I would totally recommend checking Fizzcode and Satou's Ao no Exorcist dj's out!