SOLVED. Romance(?) book about a boy who makes a promise to stop talking after he says something stupid in a fight with his best friend over a girl. Spoilers ahead. [s]

[Toby]

I don't remember the title, author's name, or characters' names.

I do remember that it was rather small and yellow. I checked out the book from my school library in TN in 2022.
There was a character in the book who had their name listed in a phone book as Batman, their real name was something funny, but I can't remember what. There was something in the book referred to as "the funny" which was just the main character mishearing things and/or making puns out of them.
Anyways, the main character gets in a fight with his best friend and afterward decides he's never talking again and they use napkins, sticky notes, dry erase boards, etc. to talk. The book had quite a few sexual references, (view spoiler)[The main character ends up getting very close to the girl he likes, but loses her after they attempt to call the "Man, Bat" in the phone book. Love interest and batman do the naughty and main character finds out and gets sad. He ends up going to a party where he breaks his oath to ends up talking to a girl that he finds he has a lot in common with (hide spoiler)]

[Brenna]

I Can't Tell You by Hillary Frank

[Toby]

Brenna wrote: "I Can't Tell You by Hillary Frank"

That's it, thank you so much.