To school

Josh went downstairs. "I gotta get to school to see if this is a real thing, he thought." Josh was a senior, and seeing as it was the end of the year, everyone in his classes at school was a senior (at least 18 years old), too. He was dying to see if any of his classmates would really openly masturbate.

As Josh got to the bottom of the stairs, he saw his older sister Kelly sitting on the couch in the living room. "Hey, Kelly," Josh said, rushing toward the door and not paying much attention.

Kelly didn't respond. Before he got to the door, Josh stopped to repeat himself, turning to look at his sister. But before he could get any words out, he saw what she was doing. Kelly had pulled her jeans down to her ankles, and her right hand was jammed into her panties. She had taken her top and bra completely off, and her perky, athletic little tits jutted out from her chest. In her left hand she was holding her phone and looking at some kind of noisy porn. Josh almost gasped and the sight of his sexy 21-year old sister frigging off openly, her right hand rubbing at her pussy with amazing speed. She didn't seem to even notice Josh standing there.

"Oh my god," she moaned, pressing her eyes shut, throwing her head back, and arching her back. Josh grew hard as stone instantly. Mesmerized, he stood in the doorway and watched the show. "I think . . . ha . . . I think it's gonna come," Kelly panted. And with her hand flying under her panties and over her clit, Kelly screeched, "Yes! Now! It's coming!" Her body convulsed with a shudder, and she thrust her pussy up in the air rhythmically as each orgasmic contraction surged through her, moaning lewdly with each spasm.

Josh had never seen anything so sexy. It took every ounce of his willpower to resist fishing out his cock and pumping it to orgasm right then and there. As she regained full consciousness, Kelly finally noticed him. "Oh, hey brother," she said casually, her still-bare breasts glistening with a sheet of sweat from her vigorous masturbation session.

"My pussy was positively aching this morning. I needed that cum big time." She smiled at him. Josh stared back at her, stupefied and speechless. "You better get in your car and get going, or you're gonna be late," Kelly chided, as if her masturbation session was the most normal thing in the world.

"Uh. Oh. Yeah. See ya sis," Josh spat our. He took one last long look at his smiling, mostly naked sister. Then he grabbed his keys, darted out the door, jumped into his car, and started the drive to school.