Maddie's heart was pounding in anticipation. Revenge, finally, after all the pranks her brother, Toby, pulled on her. Pouring cold water over her in the shower, rigging the kitchen sink to spray water on her, hiding all her spandex shorts before her cheerleading practice. She'd had enough. Her big plan: watch a scary movie with her younger brother and then dress up as the villain to scare him. She had a mask on and was hiding under his bed, wondering why it was taking him so long to head to go to sleep. Their parents told them they were both too old to be pulling this kind of crap at 20 and 21, but she did it anyways. He'd started it.
Another 5 minutes passed before the door opened. She spotted his feet first, then looked higher up to see a towel. That's where he had been. She was waiting for the opportune time to pop out, but he threw his towel down and plopped in his chair where Maddie had an view of his bottom half, a little bit obstructed by the mask. She was wondering if she should just pop out or wait until he got dressed, but quickly realized what he was doing on his computer.
"Fuck she's so hot," Maddie heard a moment before the infamous drum sound coming out of his speakers.
Surely she had to come out at that point, her chance to scare him was slipping away. But a small voice in the back of her mind caused her to stay put. She took off her mask. Maddie heard two lotion pumps and a low groan from Toby, her face buried in her hands in embarrassment after she heard it. A cheesy line about a step-sis followed.
"Oh fuck Maddie I can't believe what you wore today."
Toby was talking... about her? She thought back to what she had on, just a white tank crop top and some shorts. It was hot that day so her outfit wasn't out of the ordinary, but it seemed like Toby had different thoughts.
She thought it was a little weird, but was mostly flattered. She had started going to the gym a couple months ago and it seems like her hard work was paying off.
She looked over curiously, peeking at the porn he was watching, but her eyes were drawn to something else. His cock. It was massive, his giant hand not even covering half of it. His hands were somewhat of a joke in their family, easily palming a basketball even when he was younger. But at that moment, his cock dwarfed them in size. She didn't know how long she stared, mesmerized by its beauty. It wasn't just the size either, the shape was perfect. Straight at the shaft, thicker right before the head, and a cute, bulbous mushroom top that looked like it would fit right in her mouth. Or some random girls mouth.
The size of his cock kind of surprised her. Tony was a soft spoken guy, oftentimes not speaking up when he was tread on. The way he dressed and how he acted, she never really pictured him with a monster cock.
"Never judge a book by its cover," she thought.
He stroked at a constant pace, up and down, up and down, unbothered by the video he was watching. She finally glanced over at the screen and saw that the model, who was getting face fucked, looking kind of like her. Blonde hair, big eyes, small tits. She had to face the conclusion. He was fantasizing about her. It would be a lie if Maddie said she'd never fantasized about Toby that way, but never thought about it any further.
But here she was, under his bed watching him jack off to a model, portraying a step-sister, that looked a lot like her. The whole situation started some tingling down below. She reached down, underneath her shorts but over her panties, feeling a slightly damp spot where her pussy was. She started rubbing, at first slowly, then keeping in time with Toby's strokes.
"Suck that cock," she heard him tell the screen, accompanied by a moan.
She had trouble keeping her own moans down, more than once she had to stop in fear of crying out. It felt so good, more than her usual masturbation sessions.
Toby reached over and pulled open a drawer, grabbing something white she couldn't quite make out. It wasn't until he brought it to his face and took a deep whiff that she realized what it was. Her panties. It was one of her older pairs. A not-that-sexy bikini cut pair. One that was so painstakingly plain that she never notice it had gone missing. A surge of anger built up in her, but was quickly replaced with her horniness. It was kind of hot. Watching her brother thinking about her when masturbating, his big cock looking even bigger when he was close to busting.
It didn't take long after he'd pulled out her panties that he started grunting, his orgasm quickly approaching. He took a big sniff before he came, his cum shooting up before landing on his stomach, his chest. Maddie couldn't believe how much cum was coming out. How it might feel shooting this much into her. She turned away from those thoughts, focusing on herself and how the hell she was gonna get out of this mess.
Cum finally stopped spurting out of Toby's thick cock. He stayed there for a little bit, in his post cum euphoria and a little post nut clarity. He stuffed the panties back into his drawer and went to clean up, giving Maddie the perfect opportunity to sneak out, heading back to her room where she would her own very long session. Filled with dirty thoughts and her brother's cock.
------------------
The next day, Maddie carefully picked out her outfit. She had a plan. Some Nike pro shorts and a matching sports bra, she'd tell him it was comfortable and that she'd workout later. She was in the kitchen when Toby came in, hungry and looking for breakfast.
"Hey Mads, what's for breakfast?" He said nonchalantly, acting like he hadn't been jerking off to his sister the night before.
"There's still a lot of eggs in the fridge, bacon too on the left," she responded just as casually, trying her hardest not to stare at his crotch.
"Doing anything fun today?"
"Probably the gym but dunno what else," Maddie said, forcing herself to say something normal instead of saying she wanted to have fun with his giant cock.
Her eyes slowly drifted down when she determined he wasn't looking at her. When he walked, she thought she could catch a faint glimpse.
She sat down and ate her own breakfast, forcing herself to stop staring at his shorts. To stop staring and trying to catch an outline of his huge cock. She couldn't get the idea out of her head that a monster was hidden so close by.
After breakfast, Maddie offered to hand wash the dishes even though it was usually Toby's job.
"You sure? Let me dry at least," Toby said.
She nodded, happy for her to get an excuse for being around him. She more than once bumped against him, trying to get her Nike pros to brush against his cock, trying to get a feel. She could tell he was a little embarrassed and a little hard, shying away from her.
Toby had always been a little bit of an introvert. Staying in his room a lot and more recently staying in their garage gym. He spent a lot of time in there, his safe space, and it showed. Maddie could tell, with his large muscles and even bigger cock, he'd be a hit with the girls once he crawled out of his shell. That's what Maddie tried to convince herself that it was what she was trying to do. Give Toby more confidence. Not that she was trying to feel that hard, girthy cock inside of her.
Toby ran back upstairs after breakfast. Maddie could guess what he was going to do. She smiled to herself, thinking about what to do next.
------------------
The next step was obvious. Movie night. Toby needed more experience with close contact. It totally wasn't a way to feel his hard cock. No way. That night she found herself right next to Toby, their parents working late. She slowly inched her way towards him. They were watching the sequel to the first horror movie. She acted scared, burying her face against his arm when a jump scare happened.
"Mads it's too hot, stay on your side."
