Penelope probably had a good twenty minutes left to be under the spell of the cupcake. That was plenty of time for them to get in some quality time in Ginny's bathroom. She kissed him back hungrily but broke the kiss soon after, her hands already fumbling with the button and zipper on his trousers, hands shaking from the effect of the potion.
"Charlie, I might very well love you and all that, but if you don't hurry up I might have to hex you and you know I'm a far better duelist than you are," she said, looking him straight in the eye.