"Akutai" series by Fujiyama Hyouta. But I don't remember in which series the smell fetish comes. It might be the 2nd/3rd one.
«[]» Scent Fetish
http://www.mangago.zone/read-manga/otona_keikenchi/
http://www.mangago.zone/read-manga/koisuru_futari_no_taion/
http://www.mangago.zone/read-manga/toubou_kinshi/
http://www.mangago.zone/read-manga/the_inheritance_of_aroma/
http://www.mangago.zone/read-manga/shampoo/
http://www.mangago.zone/read-manga/kimi_no_tsuku_uso_to_hontou/
http://www.mangago.zone/read-manga/body_talk_paradox/
http://www.mangago.zone/read-manga/yasahikushite_yo/
http://www.mangago.zone/read-manga/oishii_otoko/
http://www.mangago.zone/read-manga/kimi_note/
Woahhhhh Thanks so much for responding!!
Yaoi where a guy has a smell fetish??