they're home alone for the weekend so Mel takes the opportunity to drug Frank with an aphrodisiac and watches the symptoms develop (restlessness, the obvious tent in his pants he tries to hide, flushed cheeks, tugging at his shirt as he starts getting warmer etc) until he retreats to his room for a good chunk of time even though this is usually when they'd snuggle up on the couch with a movie. She listens through his door and can hear him putting so much effort into being quiet but it doesn't matter anyway because the sound of him furiously jerking himself off is loud enough she could probably hear it from her own doorway down the hall. Finally she knocks on the door and asks if he's okay and he's kind of scared at this point so he tells her something is really wrong. And when Mel asks him to describe what he's feeling he gets embarrassed and barely mutters out that he's been painfully hard for over an hour. She asks if he's tried to make it go away and he gets even shyer and says of course he did but it didn't help. And Mel asks him how many times he tried just so she can watch him squirm even more when he tells her he already came three times. When she suggest she could help he nearly chokes and starts blabbering that he's fine and it'll go away eventually and he's just taking a break but he's sure the next one will fix it but she climbs into his lap and then he's changing course and saying they shouldn't, they can't, she's his little sister and this is wrong. And Mel pulls out her trump card, pouts and him and says the magic words but I want to because she knows very well that he'd give her anything she asked for. So they wind up fucking all night and Frank cries at least once because it's so much, too much and he's so ashamed that he's been dreaming of this for far too long but then Mel is there telling him he's doing so good, that he's so good to her, and that she's been dreaming of this for just as long as him and she always knew he wanted her this way but would never cross that line because he loves her too much and she loves that about him, that he cares about her so much and would never do anything to hurt her which is why she did this, why she'd been saving herself for him, just for him, because she's been his since the day she was born and they were always meant to love each other like this. And when he's finally spent he collapses onto her, panting out thank you thank you thank you, I love you, you're it for me, Mel, there's never gonna be anyway else. And they fall asleep in each other's arms, Mel still leaking cum on the bedsheets and she's so happy and satisfied she falls into the deepest sleep she's ever had. That's all :)