"There are a lot of things Mitch wouldn't mind losing sleep over; getting laid, partying, writing music.
Being woken up periodically by the sounds of loud, bed-shaking and (apparently) toe-curling sex from upstairs is definitely not on that list."
Scott and Mitch's upstairs neighbor begins to keep them from getting proper amounts of sleep. It begins to affect their work, their social lives, and their relationship.
So, tensions break.
(Smut and a lot of fluff. Not much conflict. Happy story.)