"Overkill"
It had taken years, but by senior year of high school, Usagi was no longer the clumsy, awkward girl she had been. She wasn't much taller than she'd been, but her long legs gave the illusion of height. Her figure had filled out from its former flatness, lending curves that drew the eye. Her face had lost some of its roundness, becoming heart-shaped and accented by large blue eyes and rose-petal lips. The only thing that hadn't changed was her long golden hair. She didn't really notice the changes, but Mamoru did.
Apparently, so did all the boys at her school.
It started off simply enough. On Valentine's day, a boy slipped a note in her locker, asking her on a date. Usagi had blushed when she told Mamoru about how she'd explained to the boy that she was flattered, but she was in a relationship.
But it didn't end there. Minako laughingly told him about a conversation she had overheard between two boys about how one should attempt to approach Usagi to ask her to dinner. A month later, Mamoru walked into Crown Arcade to see a boy leaning on the table where Usagi sat, waiting for him. His face had gone white when Usagi introduced them ("Oh, Kazuo, this is my boyfriend, Mamoru.") and had rushed out.
So Mamoru did the only rational thing he could think of.
When he opened the door to his apartment to let her in, he laughed at the sight that greeted him. Usagi stood at his door with an enormous bouquet of roses in her arms, blocking her vision. In hindsight, it was a rather large bouquet.
She shoved it into his arms and closed the door behind him before going into the kitchen to get a vase. As she filled it with water, she said, "They're lovely, Mamoru, and they certainly proved your point. The entire school now knows that I am very much in a relationship."
It wasn't jealousy, Mamoru reflected as he pulled Usagi in for a kiss. It was simply sending a very clear message to any silly young boys who thought they stood a chance with his Usagi.