Haikyuu dj

yep, just look through all of these
https://myreadingmanga.info/tag/gusari/

Beware of the website my reading manga because the ads are horrible and just...porny. So here is my favorite one and you should be able to find all of them clicking through the authors works. You also could have searched for Given here and found it through the authors works as well.
http://www.mangago.zone/read-manga/haikyu_dj_shisseishou_oikawa_tooru_no_hanashi/

OMG how can I not think about that ur right I feel so dumb rn ┗( T﹏T )┛and thanks for warning

Back again, because this is actually how I got in to Yaoi and got obsessed with this author. Its actually hard to find the order of things because all the DJs are uploaded as one shots. So just read the comments so you can kind of know how. This was my intro to omegaverse and I love it: I(I think she's mostly a Iwa and Oikawa shipper.
1 http://www.mangago.zone/read-manga/haikyu_dj_tanoshii_jogoku_wo_irodoru_nara/
2 http://www.mangago.zone/read-manga/haikyu_dj_tanoshii_jigoku_wo_irodoru_nara/
3 http://www.mangago.zone/read-manga/haikyu_hikari_no_ko_doujinshi/hs/hs_chapter-1.5/
4 http://www.mangago.zone/read-manga/haikyu_hikari_no_ko_doujinshi/hs/hs_chapter-1.5/
5 http://www.mangago.zone/read-manga/haikyuu_hikari_no_ko_4/

Thank you so much (づ￣ ³￣)づ