I Swear We're Not Gay! (Eren × Levi smut!)

Eren and Levi fell in love and started dating in high school. Both Levi and Eren have kept it a secret and simply covered it up with "we're best friends". One day, Levi's mom announces that she won't be home until that next morning and that he could bring a friend over so he wouldn't be lonely. What will happen when L...