You catch your sister doing something...strange. Did she really just make that can larger just by starring at it? Your friends have noticed that her tits have been looking awfully big but you didn't believe them. Now you have proof that something is going on! She tries to hide it but it's no use. She tells you she has the power to make things larger but acts super embarrassed about it. It's not a cool power like flying or invisibility...but you think it's quite useful. You BEG her to try and make your dick bigger. After bribing her with a new videogame she caves and before your very eyes your cock grows! You tell her it's starting to hurt which is kinda weird, then you start to tingle. It wasn't the super power that made you feel so weird, it was the feeling of your sister's hands wrapped around it that made it tingle! You're a pervert...but your sister is a size queen. Seems like a match made in taboo heaven.