Stay with Anna

"I think I'll stay actually. I'm feeling a bit tired."

"That's fine James," Katherine says. "Why don't you find something to do with Anna? She's probably bored out of her mind right now."

The parents and your Grandma leave the house, leaving you and Anna alone. You sigh and decide to grab a snack before seeing what Anna is up to upstairs.

"Did they leave?" You see Anna by the top of the stairwell looking down at you.

"Yeah. Why?"

"Good. Come up. We're going to watch a movie."

You wonder what movies your grandma has—probably old classic black and white films.

You follow your long brown-haired sister to Grandma's bedroom. She turns her head around and flashes you a playful smile which you reply with a raised eyebrow. When you enter the room and sit on the bed, Anna heads to the T.V. and turns it on. The T.V. blinks and the picture slowly comes to life. There really is a movie going on. It's a superhero movie with a 60-year-old heroine as the main character. There was something strange about this movie after 15 minutes in. That's when you realize what it was when the heroine accidentally ingests pink fumes from a lab accident and transforms from a short flat chested old lady into a 6 foot tall big breasted young bimbo. Then the entirety of the lab team, who were strangely all tall muscular men, become hypnotized and take off their clothes, gangbanging her.

"Anna, this is a porno..." you turn your head to see Anna laying down on the bed and flicking her bean. "The hell? What are you doing?"

"Oh lighten up you dweeb. There's no one here beside you and me, and I need some relief."

You feel a strange urge to start jerking off as well. You can't quite put your finger on it, but you think it had something to do with being in Grandma's house. Anna isn't one to care if you accidentally see her naked but she would never start jerking off with you in the room...or maybe she would. She is pretty crude after all.

You shrug and lay down beside her and start jerking off as well. Your sister eyes your dick briefly before going back to the screen. The porno gets intense and you stop when one scene ends and resume when another starts.

"I can't get off. This porno sucks." Anna says. She gives you a funny look. You wonder what she's up to when she smirks and grabs your hand and places it on her hairy pussy. "Jerk me off."

"Ew, are you dumb..." you move your hand away. Anna looks at you annoyed but doesn't say anything. You sigh and put your hand back on her vagina. She's your sister after all. You both look out for each other, even in this strange situation.

She giggles, "Love you, bro."

"Please don't say that. We're already doing some weird shit right now."

"I know. I don't why I'm making you touch me, hehe. Maybe I'm high. You think Grandma puts weed in her cookies?"

"I hope not..."

You watch as Anna moves her hand and starts jerking you off.

"Ohh yeah. Fuck, this feels much better when it's not my own hand," Anna says, sucking in a breath.

"Yeah, ugh, me too."

Her pussy starts getting wet from you rubbing it back and forth. You can smell the musky pungent odor emitting from it. Occasionally she guides your hand, showing you how to move and where to rub. Her hands too feel nice as she touches your cock in gentle, tender strokes and even when she massages your balls. You feel like your balls are safe in her hands. The porno keeps going but you don't pay attention to it. 60% of the time you're staring at Anna instead and she does the same. Eventually, Anna kicks her pants and underwear off her legs and you do the same.

"My, ah, hand hurts. Scooch in closer," she moans softly.

"Y-Yeah."

You both scooch over on the bed laying on your sides, facing each other. This time you both are completely ignoring the porn and staring at each other's faces and genitals.

"Haha, you should see your face right now," Anna chuckles, "It's like, doi!"

"Sh-Shut up." You ram your fingers inside her pussy which elicits a moan.

"F-Fuck! That feels good! Holy shit bro!"

A while later you both are still jerking each other off but none of you can cum. At first, you felt good at being able to last this long, but now it just feels painful.

"I can't cum, Anna. You suck at jerking people off."

"I should be saying the same. I'm not getting off either."

Your sister's eyes shine with a light that only happens when she gets an idea. You realize she might be up to something.

"James, stick it in."

"What? Are you crazy? This is as far as I'll go."

"I fucking need it, James! I'm so **** to cum!" She says wide-eyed. "You're lying too. Your eyes twitch when you do." She then pushes you down on your back and straddles your waist. She positions your cock over her hairy snatch with a determined look.

"Wait, stop!" You cry, "This is dangerous. At least find a condom!"

"J-Just pull out or something!" Anna moves down slowly inches away from penetration, but you find the strength to try to struggle off from under her. "Quit squirming or I'm gonna slip," she yells.

And slip she does. Right onto your cock, balls deep. Her pussy makes an incredibly lewd wet sound due to how damp she is.

"AHH! OH F-FUUCKK!" Anna's body shivers and convulses on top of you, a jet of liquid sprays out her pussy and wets your crotch and stomach.

You can't take it anymore either. It was as if your orgasm was being held back by some magical **** that lifted when you inserted it fully into Anna's pussy. Your orgasm lasts for about a minute of nonstop cumming and Anna herself drops down on top of you, still orgasming herself as her body shudders and pussy squirms from the inside. From some primal **** within you, you feel good at having cum inside a vagina, sister or not. You thrust your hips up and grab Anna's shapely ass and press her crotch down harder, making sure your sperm goes in as far as it can.

A few minutes later you both recover from your pleasure high, your dick softening up in your sister's cunt and you release your **** grip on her ass.

Her breathing comes to a steady rate and her heartbeat slows down normally. Anna moves her head up in front of yours, concern written all over her face as she stares you in the eye. "Crap. What did we do."