The afternoon sun filters through the blinds of {{user}}'s study room, casting golden stripes across the desk where Cha Sumin sits explaining derivatives. Her red hair is pulled back in its usual formal bun, though a few strands have escaped to frame her face. Her white blouse is buttoned conservatively, but still manages to hint at the large breasts beneath. Her ruby red eyes narrow slightly behind her square-rimmed glasses as she notices {{user}}'s gaze drifting away from the textbook. "So if we take the limit as h approaches zero..." she continues, tapping her pen against the paper. Her voice remains professional and measured, despite {{user}}'s obvious disinterest. She shifts in her chair, crossing one leg over the other, causing her pencil skirt to ride up slightly. The movement catches {{user}}'s attention, his eyes darting to her thick thighs. A small, almost imperceptible smile touches her lips as she notices where his gaze has landed. "Are you following this, {{user}}?" she asks, deliberately uncrossing her legs and leaning forward to point at the equation. As she does, she allows her legs to part slightly, the hem of her skirt inching higher. Her ass shifts on the chair as she adjusts her position, making sure to keep the textbook in focus while simultaneously giving {{user}} a better view of her legs. "The key to understanding calculus," she continues, her voice dropping to a slightly more intimate tone, "is paying very close attention to... details." She looks up, catching his eyes directly for the first time since the lesson began. Her ruby red eyes hold his for a moment before deliberately dropping back to the textbook. "Now, shall we continue? I need your full attention for this next part."

Her cheeks flush slightly at the mention of attention, but she tries not to let it show. "Good," she says, nodding encouragingly as she continues explaining derivatives. Her hand moves faster over the paper, revealing glimpses of soft, pale skin beneath her blouse. When she leans back in her chair again, her breast press lightly against the fabric of her bra, outlining their curves. "You see, calculus is like a puzzle," she says, turning another page in the textbook with a flourish. "And if you miss one piece, you'll never understand how it all fits together." Her gaze meets his once more, this time holding steady as if daring him to look away again. "So let's make sure we don't leave any pieces out when we study this chapter, shall we?"

Her lips quirk into a small smile at his obvious lack of focus. "Well, you're doing an excellent job so far," she teases, trying to keep the mood light despite her frustration with his inattention. "Just remember, if you have any questions or need help understanding something, don't hesitate to ask." She glances down at the clock and adjusts her glasses before continuing. "Alright, we should probably take a quick break now. You can stretch your legs or get a drink if you like."

The hint of flirtation in her tone is unmistakable as she stands up from the chair, stretching languidly and allowing the movement to emphasize her curves once more. "That way we'll both be refreshed for our next lesson."

A warm blush creeps up her neck at his words. "Alright, let's skip the break then," she replies, trying to keep her voice steady despite the flutter of butterflies in her stomach. She turns back towards the desk and pickes up a pen, tapping it idly against her closed palm as she waits for him to sit down again. As he takes his seat, she continues with renewed confidence, using her body language to emphasize each point in a way that's impossible not to notice. "So, let me show you an example of how we can apply these derivatives to real-world situations..." Her voice trails off slightly as she glances up at him from beneath her lashes, her ruby red eyes meeting his once more before darting back down again. The air between them seems charged with a new energy, making every word feel like an intimate whisper despite the room'

"...And as you can see, by understanding these tiny details, we can make big improvements in everything from medicine to engineering," she says, her voice barely above a whisper now. Her gaze doesn't leave his face as she speaks, their connection growing more intense with every passing second. "Don't you think it's fascinating?" She leans forward slightly, resting her elbows on the desk and cupping her hands around her mouth to emphasize her point. Her breasts graze against the fabric of her blouse in the process, making them even more prominent beneath. Slowly, she begins to rock back and forth on her chair, causing the hem of her skirt to ride up further with each movement. Her thighs brush against the armrests as if by accident, but there's no denying the deliberateness in her actions now.

Her lips quirk into a small smile as she listens to his admission, her heart racing with anticipation. "Oh really?" She asks, sounding surprised but playful. "Then I suppose we'll have to spend some extra time going over it, won't we?" Her voice drops even lower now, almost breathless with excitement. Suddenly, she leans forward even further until their faces are only inches apart and her breast grazes against his arm. "Maybe," she whispers conspiratorially, "we could find a way to make it fun." Her hand finds its way to his upper thigh, massaging gently as her thumb brushes against the inseam of his pants. The warmth between them seems to intensify with each passing moment.

The warmth between them intensifies as their breath mingles and their bodies press against each other. She could feel his erection tenting through his pants, and it sends a shiver of excitement down her spine. With a soft sigh, she nods slightly, relishing the closeness they share at this moment. "Yes," she whispers, "I'm doing this for the money." Her free hand moves up to cup his cheek, tracing a gentle circle on his skin as she continues, "But I won't lie... it's hard not to want you." As her fingers trail lower to caress his jawline and neck, she leans in even closer, their lips only inches apart now. Her heart races wildly in anticipation of the moment when they'll finally meet in a passionate kiss. "You're so handsome, Levi... So strong... It's intoxicating being

As their lips meet in a soft, gentle kiss, time seems to stand still for Cha Sumin. She closes her eyes and allows herself to enjoy the feeling of his lips against hers, his strong arms wrapping around her waist and pulling her even closer. His touch sends shivers of pleasure racing through her body, making it difficult for her to remember why she was here in the first place: teaching him math. Her hands roam freely over his chest, tracing lines up towards his neck as they kiss deeper and with more passion. Her nipples harden beneath her blouse, pressing against the fabric of her bra, begging for release. She moans softly into their kiss, feeling herself growing wet between her legs at the intensity of this moment. Her body presses flush against his, seeking even greater contact as she loses herself in the sensations overwhelming her. There's no denying it any longer: Levi has

Cha Sumin blushes as she processes his words and the implications they hold. She takes a moment to compose herself before slowly nodding her head in agreement. As he stands up from his chair, offering her a hand to help her off the desk, she gently places her palm against his cheek, guiding him back down into his seat so that she's straddling his lap with her dress hiked up above her knees. Her breath hitches as their bodies press together in an even more intimate way, her breasts flattening against his chest and her ass grinding against his erection through the fabric of their pants. With a soft moan, she leans forward and kisses him again, this time with renewed passion and determination. Her hands find their way to his hair, tangling in the strands as they deepen their kiss, exploring each other's mouths with

Pulling back slightly, she looks deeply into his eyes. "You're right," she whispers hoarsely. "We need to focus." Her breath is ragged, her cheeks flushed with desire as she takes a moment to compose herself before continuing. "Derivatives... They measure the rate of change..." Her voice trails off as she feels his erection pressing against her through their clothes, sending shockwaves of pleasure coursing through her body. Unable to resist any longer, she grinds against him, moaning softly into his ear before returning her attention to the lesson.

Her heart races at the suggestion, but she resists. "No," she says firmly, trying to focus on the lesson and not give in to their desires. "We have work to do." She leans forward, brushing a stray strand of hair from his forehead before continuing with the lesson, her hands moving gently over his chest as if in reassurance that she's still there for him despite their growing desire.

With renewed determination, Cha Sumin clears her throat and begins to explain the concept again, doing her best to ignore the way his strong arms feel around her waist and the heat radiating off his body. She moves one of her hands downward, guiding it towards his lap, hoping that focusing on math will help them both resist temptation for now. As she explains each step in the process, she uses her other hand to guide his over the paper, showing him how to solve the problems, their skin brushing together with every move.

Her body trembles slightly as she feels his hand brush against hers on the paper, their connection so intense it's almost painful. She forces herself to concentrate on teaching him, despite her own desires surging beneath the surface. The longer they sit like this, skin touching and breath mingling, the harder it becomes for either of them to focus on anything else.

With a quiet sigh, she leans forward once more, resting her palms flat against his chest as if in supplication. Her breasts graze against his skin, making her nipples harden even more and sending shivers down her spine. Her gaze drifts upward to meet his eyes before dropping back down again, her cheeks flushing bright red with embarrassment and desire.

Her heart races as she feels his lips brush against hers, but she tries to remain strong, focusing on teaching him despite the temptation that's beginning to overwhelm her senses. With a shaky breath, she pushes herself back up onto her hands and knees, arching her back slightly to give him a better view of her curves. Her blouse slips down further, exposing more of her cleavage and making her nipples stand out against the lace of her bra. "Levi," she whispers, her voice shaky and breathless. "I know this is hard for you... but we really need to focus." She leans back in again, their bodies pressed flush against each other from chest to thigh. His erection presses insistently against her through their clothes, making it difficult for her not to give into temptation.