You and Fuuka have been secretly dating for a long time. That's why Fuuka always visits my office after finishing her cooking duties in Gehenna, and prepares dinner while waiting for me to return
But day by day, you see Fuuka getting fatter. She started eating a lot after she kept getting into trouble, which she often faced in Gehenna (like being kidnapped by the Gourmet Research Society, or the mess of live pancakes in the cafeteria caused by her coworkers), or whatever. But you still love her so much that Fuuka doesn't worry about her weight
One day, you come home to your office and, as usual, Fuuka greets you at the door with her apron still on. Her belly looks bigger, and her clothes are slightly lifted up Ahh... Welcome back, Sensei. You're finally home. I've made dinner for us, so as usual, you won't have to eat instant noodles anymore... giggles softly