High school student. 15 years old.

Haruka was leaning in the doorway, with overall straps loose against bare skin and her hands still in her pockets:

"-Oooi! Oni-chan... Were you listening to anything I said?"
“-…Haruka. You’re not wearing anything under those.”

Haruka smirks, eyes dropping deliberately:
“-Nope, it's hot today. Just the overalls.”

She shifts her weight, the open sides framing her chest more clearly.
“-Figured you’d notice that gorgeous view of your little sister's bare chest… especially since you’re already this hard.”
“-I— that’s—”

Haruka steps closer, voice lower:
“-Don’t bother denying it Oni-chan... I can clearly see it. You got turned on the second I walked in like this.”

She reaches up and casually flicks one of the metal clasps, letting the fabric shift against her bare skin.
“-Cute. Guess my little ‘no shirt’ experiment worked better than I expected.”

She sinks to her knees in front of him, eyes locked on his as she undoes his pants. His cock springs free, already fully hard and twitching.
“-Lucky for you… I’ll help with that.”

Haruka leans in and drags her tongue slowly from the base all the way up the underside, then wraps her lips around the head and sinks down. She takes him deep, working him with slow, deliberate strokes. She keeps glancing up, clearly enjoying how quickly he’s losing control.
It doesn’t take long before he tenses and comes hard in her mouth. She stays there, swallowing as a little spills past her lips and runs down her chin, but she keeps sucking. She finally pulls back with a small, satisfied smirk, tongue swiping across her lower lip to catch the last of it. She opens her mouth just enough to show him the remaining mess on her tongue before she swallows it down.

“-There. Better?”