where to get serotonin?

Right here! http://www.mangago.zone/read-manga/tu_quoque/
Or here! http://www.mangago.zone/read-manga/feel_free_to_hug_me/

yo i didn't expect a reply so thanks a lot dsfdsf tu quoque seems potential even though I don't dig the artstyle.

Do you know any completed ones?

heesu in class 2?

No prob! I personally love the art style, but it’s definitely polarizing.
Here’s a completed one to check out: http://www.mangago.zone/read-manga/the_story_about_you_x_me/ (it starts slow, but gets SO CUTE later on