He should see what's happening inside

Mason raised an eyebrow. This asshole was talking about his sister in that way? The words hit him like a slap. He felt heat rush to his face, part anger, part morbid curiosity. He decided to peek in through the cracked door to see what was happening.

He moved carefully, heart suddenly pounding hard in his chest. The gap in the door was just wide enough. Mason leaned in, one hand resting lightly on the frame so he wouldn’t accidentally push it open.

What he saw made his stomach drop and his mouth go dry at the same time.

Serena was completely naked on the floor of his bedroom.

She was on her back on the cheap carpet, knees bent and spread obscenely wide apart, giving him a perfect side-profile view of everything. Her massive breasts spilled outward, heavy and full, the dark nipples stiff and pointing toward the ceiling. They rose and fell quickly with every shaky breath she took, jiggling slightly with each thrust. Her body really was something else, hourglass shaped and tight from all the gym sessions she did at university. Flat stomach, flared hips and those thick, toned thighs that looked strong enough to crush someone. Between her legs her pussy was visibly stretched around the thick handle of Mason’s baseball bat. The smooth wooden shaft was slick and shiny with her juices as she slowly worked it in and out of herself in a steady, deep rhythm. Each push made her hips lift off the floor a little, the fat head of the handle disappearing between her puffy, swollen lips before sliding back out again.

Her long jet-black hair was splayed messily across the carpet. A few strands stuck to her flushed cheeks and forehead. Her light brown eyes were half-lidded, unfocused, staring blankly toward the laptop that sat on the low coffee table nearby. The webcam was pointed straight down at her, capturing every filthy detail from above. Because Mason was peeking from the side angle through the cracked door, he couldn’t see the screen clearly, just the edge of the laptop and the faint glow of the call. He could hear the man’s voice loud and clear though.

Serena kept repeating the same phrase in a soft, broken moan, voice thick and obedient.

“I’m a fat titty slut… I’m a fat titty slut… thank you for using my cunt…”

The man on the video call laughed, low and satisfied. Mason couldn’t see his face, he only heard that cocky, mocking tone.

“Look at those fat fucking udders bouncing while you stretch your own hole with that bat, whore. You really are just a set of holes, aren’t you? Say it again. Tell me how much you love being a brainless cumdump for your masters.”

Serena’s grip tightened on the baseball bat. She pushed it deeper, a wet, obscene squelching sound filling the room as she obeyed without hesitation. Her heavy tits bounced harder with the motion.

“I love being a brainless cumdump… my pussy belongs to you…”

Mason’s mind reeled. This wasn’t his sister. Serena never talked like this. She was the one who helped him with girls, who told him to respect women, who once spent an hour lecturing him about not watching degrading porn. Yet here she was, legs spread wide on his bedroom floor, fucking herself stupid with his own baseball bat while repeating the filthiest shit he had ever heard. Her body trembled with obvious pleasure every time the thick wood stretched her open.

He should have backed away. He should have closed the door and pretended he never saw anything. But his feet wouldn’t move. His eyes kept dragging over her body from the side, the way her massive breasts jiggled and slapped together every time she thrust the bat into herself, the slick shine of her juices coating the wood and dripping down onto the carpet, the way her hips rolled up greedily to take more like she couldn’t get enough.

Part of him felt sick. This was Serena. His big sister. The same girl who used to sneak into his room when Mom was yelling and hold him until he stopped crying. The same one who bought him his first proper gaming setup with her own money. But another part, darker, hungrier, couldn’t look away. He had always had a crush on her. He’d tried to bury it for years, telling himself it was just because she was hot and he was lonely. Seeing her like this, completely naked and broken open on his floor, made that old feeling roar back to life whether he wanted it to or not.