Peeking

Morning, Mabel

Coming to Gravity Falls, Oregon for the summer had become a family tradition. Their parents would ship them off to the small town while they took romantic vacations, second and third honeymoons, and trips to vineyards. Places where adults normally wanted to go, if they didn't have their kids to care for. So, as always, the Pines twins were sent to the Mystery Shack. Even as they got older, they would lodge together in the attic of the old wooden building. Grunkle Stan was too cheap to invest in so much as a curtain to separate their beds.
Mabel was always the one to wake up first, therefore she was the one to use the shower first. Dipper would wake up each morning, inhaling her peaches 'n' cream body wash scent, the steamy bathroom full of the smell. Drops of water littered the floor from where she emerged from the bathroom and changed into her sweater for the day. He ached as he thought of how she was in the same room with him, nearly in the nude, while he remained sleeping, dreaming of the very scene that was going on in reality.
That evening he set his phone alarm to wake him up at 6. He would force himself to wait until Mabel got up. As he got into bed, he placed a mirror he swiped from Lazy Susan on the floor under his bedside table. The now 16 year old boy tossed and turned in his sleep, even waking up a few minutes before his alarm in anticipation.
Like clockwork, Mabel rose from her bed and yawned exactly at 7 am. She swung her legs out from under the bed and walked toward the bathroom in a slightly too short night gown. Dipper forced himself to face the wall, the mirror in his hand.
Twenty minutes had passed when the bathroom door opened, Mabel walking out clad in only a pair of star speckled panties, one large glittery star in the center of the front. Her long brown hair, dripping onto the floor, covered her breasts. He smelled the peachy scent wafting from her damp form. He adjusted the mirror so he could see her as she changed. First, she took a bra from her drawer, one with two large hearts on each of the cups. She bent forward, her seemingly endless locks falling forward over her head where she wrapped the chestnut mass in a white towel. Though he couldn't see her front, he took pleasure in imagining it. Perky, pale breasts with pink nipples he would take no hesitation in licking and gently biting until she moaned his name.
The bra was fastened and she looked in the mirror, taking a bottle of lotion from her bedside table and rubbing it over her smooth skin. Dipper nearly drooled as he saw the water droplets fall from the stray locks of hair and fall down her form. In her reflection, he could see them cascade down the valley between her breasts and down her small waist, the cloth of her panties becoming darker from the water, see through in the spots where the stars were white.
As she combed her hair, Dipper imagined himself tugging on the hair so close in color to his own, watching her brown eyes light up as he unhooked the bra and trailed his tongue down her chest and stomach, tugging down her panties with his teeth. He would delight in watching her form goosebumps and shiver with a quiet mewl.
When he reopened his eyes, Mabel had already put on her skirt and sweater, this one black with metallic threads of all different colors wound through it. In fact, the girl was standing next to his bed. Their eyes met in the mirror he held in his hand and he groaned softly. "Morning Dip Dip." She said, leaning over him with a smile, her smile revealing her perfect white teeth.
"M-morning Mabel."
"Ya know, it's impolite to peek without asking." She poked his cheek as he turned in his bed to face her. He stuttered as his face grew redder and redder at the shame of being caught oggling his own sister. "Don't worry, I'll let you off the hook. This time." She glanced from side to side and placed a kiss on his cheek, her lipgloss leaving a glittery patch on the skin. She winked and laughed before skipping out of the room, Waddles waiting at the door for her.