Lavender

Ron's on again off again Girlfriend/Hookup was a subject of many of Harry's guilty fantasies. Her long blonde hair, blue eyes and the way her breasts and ass had ballooned out over the last few years made it impossible to resist. Plus, she and Ron were never the type to remember a silencing spell whenever she came over for a late night and it had given Harry plenty of chances to stroke off listening to the two of them.

A moment of searching found the blonde locks he needed and after dumping them in the altered potion (And admiring the pale yellow colour it turned) he wandered where he should make the change. Ron was away right now and if anyone asked, he could always claim that "she" was just waiting for him to come back... or he could take the chance to have a peek at the Girl's rooms, a fantasy he's had for a while now...