Below her penis is a huge pair of balls

You take a long look at her massive, coconut sized balls. They were covered in veins, easily the size of her pinky finger. Slowly pulsating, they reminded you more of a bull than your little sister... How could she have kept them hidden for all these years?

And if their sheer size wasn't intimidating enough, you could hear them producing sperm, churning like the machines at your favorite ice cream parlour. Slowly you realize, that her previous cumshot was nothing more than mere pre-cum. You could't imagine what an actual cumshot of hers would look like...

You stare at her balls for what feels like an eternity, until her moaning suddenly kicks you out of your trance. Your curiosity might soon be satisfied, as you see her already huge 7 inches long dick slowly growing erect. But instead of standing up, it continues to grow next to her legs, slowly passing her knees, you estimate her to be around 10 inches now, but her dick shows no signs of stopping.

But when it reaches her calfs, at what you can only imagine as being at least 14 inches, it finally starts to harden. Lifting her blanket up, you can finally see it in it's whole glory. 18 Inches of veiny girlcock, pulsating and standing straight like a tower. Only now, that her foreskin has been peeled back, you get hit by the horrible smell of her unwashed cock.

But only when seeing a drop of pre-cum, many times bigger than every cumshot you could ever produce, slowly sliding down her cock, you finally look at her balls. Red and swollen to the brim, looking as if they would break any moment. Just now you realise what awaits you, if she cums. Her moaning getting louder, you realise the short time you have left.

You try to run as fast as your tiny legs can handle, but it is no use, you look behind you and see a wave of cum, bigger than you could ever imagine. You get hit by the wave and nearly drown in the thick cum.

An unknown time later you awake, finding that you survived the onslaught of cum...