Surprise her and jump in now

Your lust clouding your sense, you go forward and yank apart her curtains. A magnificent sight awaits you.

Her eyes are closed as she runs one hand through her cascading hair, with the other one rubbing a bit of shampoo onto her firm and round butt. Her wet skin is spotless and even glistening under the shower, and her full breasts are standing proud, stimulated by the shower water.

She hears the noise as her eyes flutter open, and you see her eyes widen in shock and her mouth form an "O" as she stares at you.

Before she can say anything, though, you say (with the word in your mind), "Wait a sec! I can explain! I'm just here to take a look at the inner workings of your vagina using my reproductive organ. Nothing to worry about, sis!"

She seems confused for a second, then offers you a sheepish smile as she visibly relaxes. "Oh, ok! Come on then!"

A bit surprised that it worked so well, you go ahead and enter the shower behind your sister's sensual, nubile form. You lightly touch her pussy with a finger, and frown disapprovingly at the lack of arousal.

"**** with your brother arouses you", you command her.

Satisfied with her slightly accelerated breathing and somewhat moist pussy, you remove your finger and position your dick in front of her soft, shaven pussy lips. You lean forward to kiss her gently as you simultaneously push past her pussy lips and enter her cunt. She kisses you back, and moans softly into your mouth as you thrust forward and bury yourself completely inside her warm and wet pussy. Her pussy involuntarily clenches your hard dick, and you groan out in pleasure, enjoying the sensations of a pussy for the very first time, pleasure flooding your senses entirely. You pump your dick back and forth slowly. She moans in turn with you as you ravage her cunt, her pussy massaging and stimulating your cock. You gradually increase in speed as she gradually increases in moaning frequency and intensity.

The feelings you feel are as you have never felt before. Pleasure floods your senses, drowning out all others, and all you care about is your sister's soft, sensual body and her warm, wet cunt. Her breathing grows ragged as she lets out a drawn-out moan. Pumping your dick in and out of your sister's slick pussy, you groan as your sister suddenly gasps loudly and moans in ecstasy, her pussy clenching and spasming around your dick as she cums. Finally, you blow your load into her orgasming pussy, making her moan even louder as your cum mingles with hers.

The moment of pure euphoria passes, and you slowly come back to your senses. Your sister is leaning against the wall, breathing heavily, seemingly **** as a result of her orgasm's strength. Your dick is still buried fully in her, and it still feels wonderful. You almost already feel ready for another round.