Can you guys recommend me some yaoi mangas where the seme has a strong nipple fetish. I would love it if the story continues. I 'm not very fond of one shots but you can still recommend one shots if they really are very very good. xD

Maybe not solely nipple fetishy, but Hitotsu Futatsu Himitsu features a lot of nipple play. It's about a teacher who is embarrassed by his inverted nipples, and a student (who has a crush on him) offers to help "fix" his issue. I really enjoy it!

I already read it and enjoyed it like you did. Thanks anyway!
Allow me to rephrase what I said. As long as there's a lot of nipple play in it then I'm okay if the seme doesn't have the fetish. Example would be Hontou Yajuu.