How I Paid for College: A Novel of Sex, Theft, Friendship, and Musical Theater by Marc Acito is a YA book with a bisexual male protagonist and one of the funniest books I've ever read- I just remember laughing a ton reading it.

Clearcut by Nina Shengold is a novel I stumbled upon accidentally that just happens to have two bisexual male protagonists . . . you can imagine how utterly thrilled I was to just have that randomly pop up in a book where I wasn't even looking for it!

Phyllida and the Brotherhood of Philander: A Bisexual Regency Romance by Ann Herendeen didn't blow my mind, but it was an enjoyable read with an explicitly bisexual male protagonist.