In the dimly lit closet of their grandparents' house in Mexico City, a brother and sister, both still in their teens and raised in a strict household, find themselves alone. The sister, curious and horny, starts to rub her pussy through her panties, her brother watching her with growing interest. She turns to him, her eyes heavy-lidded, and whispers, "Touch me." He hesitates for a moment before giving in, his hands exploring her body, his cock hardening in his pants. She unzips him, taking his cock out and stroking it, her thumb rubbing the pre-cum off the tip. They fuck standing up, the sister's back against the wall, their moans muffled by the clothes hanging around them. They come together, their bodies shaking with the force of their release, their juices mingling and dripping onto the floor.