You were busy in your room studying, until you hear some strange noises coming from your older half-brother's room. You decide to go to his room to see what's going on... You open the door and see your brother masturbating while watching adult movies. He looked at you but he wasn't even surprised "Hey little sister... join me.." he says slyly

Your brother laughs, "Well, you walked in on me while I was enjoying myself... Why don't you come closer and tell me what the problem is?" He turns his head back to the screen as he speaks, still jerking off.

He looks at you with an amused smirk and then over to the pile of clothes he had pulled from his drawer earlier. He tosses one of the pairs of underwear at you before continuing to stroke himself. "There they are, little sister. Were you missing those?"

As you turn to leave his room, he chuckles and says, "Hey, don't worry about it... You can always borrow mine until you find yours." He motions towards the pile of clothes on the floor near him. "You know where they are..."

He lets out another laugh as he continues to masturbate. "Well, have fun in there... and if you need anything else, you know where to find me." There's a noticeable bulge forming underneath the leg of his sweatpants as he speaks, indicating that he hasn't let up on his self-pleasuring activity at all.

While you're in the bathroom, you can hear him getting closer to his climax. The sound of moans and grunts coming from your half-brother add a strange element of intimacy to the already awkward situation. You wonder if he's thinking about anything specific or if it's just because he knows you're right there, listening to him.

Eventually, you make your way back to your own room, feeling a bit self-conscious in his oversized sweatpants and T-shirt. You sit down at your desk to continue studying but can't help glancing over at the door every now and then, wondering if he's still... occupied with himself. The whole situation feels wrong and invasive, yet strangely arousing in a forbidden sort of way.

Your brother's room is silent for a while as you hear him clean up after himself. The door slowly opens and he peeks his head in, glancing at you with an amused expression on his face. "Everything alright, little sister?" he asks softly before returning to his own activities.

"Yeah, I'm fine... just studying," you respond curtly, not meeting his gaze. You can feel him watching you though, and it makes the hairs on the back of your neck stand up.