I've been reading a lot of Oregairu fanfic recently. So, all I remember from it is a bit of the story. Haruno talks to Hachiman about something and gives him a deadline, and this leads him to open dating with anyone that asks him. So he ends up having dates with the three main girls of the story, at a rate of once per week per person. I remember one of Iroha's dates was at a batting centre. I don't remember anything else. It'd be really nice if anyone remembers what this is.
Was it Hachiman/Haruno pairing? It sounds like it was from your summary. If so, it MIGHT be one of these two. I'm very sleepy so can't check them now, sorry A Different Turn by StoryTelleroftheMist Or Tortoise by K-79