(No longer) Like Siblings
 

William sits in the back of the algebra class, already bored before class could even start. He was a softhearted kid. William would get along frequently with girls due to his openness of how they looked without bullshitting them. In particular, his 'sister' as Keely called herself, was a close friend. He had begun to like her, but was awkward in that he would be afraid of ruining their relationship. These thoughts filled his mind as he looked at the back of her head.

William taps her shoulder. "Want to come over today?"

Keely turns around, "Maybe, what would we do?"

William smiles, "We could go to Movies, maybe truth or dare after."

Keely shrugs, thinking nothing of it. Keely met up at his house and he drove to the movies. She stares out the window, thinking. She was a closet exhibitionist, and not even he knew that. Under her dress was absolutely nothing. Keely imagined bending over in front of him, and the dress slides up, revealing her exposed ass. She shakes her head, he was her closest friend, she could never do that.

William drives on the streets, cold air coming out of the A/C. He glances over at the daydreaming Keely, to see if she was cold. He discovered the ai from below the seat had pushed her dress up sligthly. He turns down the cool, increasing the fan speed so shewouldnt notice the change. The cloth reveals her bare toned legs, and he forms a boner.

Keely looks at him, and he was focused on her bare legs. She followed his gaze, leading to her exposed body. As soon as the realization hit her, she began to get extremely horny. Keely looks over at his boner protruding from his jeans. She casualy hooks her dress straps in her thumbs, sliding her dress off.

William pulls over, stunned. His long time crush was naked in his car, and he was not about to pass up the opertunity to see her naked. Williams eyes admire at her as she sits, hot and horny. "Are you an exhibitionist?"

Keely nods, encompassed in the need for sex.

Two Tense
 

Great story but you need to decide which tense you’re writing it in. Half of it is in present tense and half is in past tense.

Generally speaking, it is easier to write a story like this in past tense.

If you want to use present tense then only revert to past tense if you’re writing a flashback or a character’s thoughts of previous events.

Otherwise, it’s good and I’d like to read more.

:)