Mike set his books down as he walked in the door. Another long week of high school finished with. He ran his fingers through his brown hair and stretched as he walked to the kitchen to find something to eat. His parents had said they would be out of town for the whole weekend, giving him some solitude. Mike's sister Sarah was also going to be home, but she was usually out with her friends, who didn't see her while she was off at college. She was 2 years older than Mike's 18 years, with medium length golden-brown hair and 36c breasts. At 5'6, Mike had to look a bit up to her, 2 inches taller than he was.
Mike got a soda from the fridge and was walking to his room when he heard a few moans coming from Sarah's room. They sounded erotic, and Mike being the curious guy he was, peeked through the crack in the door to see who was the lucky guy.
He blinked and went wide eyed. It wasn't a guy who was lucky, it was her best friend Vicki! They were naked as jailbirds, and Sara had her head between Vicki's legs! Mike rubbed his crotch, his 7 inch cock straining against his jeans, begging to be let out. He involuntarily gasped as he rubbed his cock through his pants and then slipped away when he saw Sara remove her head. He was about to walk back to his room when the door swung open, Sarah in all her naked glory staring at him.
"How much did you see?" She glared at him. "Enough. I'm suprised, I never thought you were bi." he smirked. Suddenly Sarah grabbed his wrist, pulling him into the room and swinging him onto the bed. "What're you doing?" he asked.
"Well, my vibe's batteries are dead and we both wanted to have some sort of male stimulation, so you're it Mike!" Sarah giggled as she held his hands down. Vicki handcuffed his wrists to the headboard, then swung her long black hair back, giving Mike an unobstructed view of her 40 D cup tits. Sarah had busied herself undoing Mike's pants, freeing his cock. "Oh my Mike. Someone's excited by all this." She grinned wickedly down at him. "No, sis..we can't..shouldn't." But Vicki put her fingers on his lips. "Sweetie, don't argue with her, she's a stubborn one."