Preferably when Kenma's either a third year or graduated. Without Kuroo around to bug him about his hair, Kenma's taken to growing it out and just leaving it in a loose ponytail for games. Cue Hinata frequently getting distracted by the thought of how [i]soft[/i] his hair looks, and how nice his shampoo smells and...

PS: Super duper gigantic brownie points for 3rd year growth spurt Kenma and hasn't-grown-a-whit-since-first-year-but-broader-across-the-shoulders-and-the-most-killer-legs Hinata ;o;