Hidden away in the cloakroom, the curious brother discovers his sister's secret. Her eyes widen as she sees his massive cock straining against his jeans. She tentatively reaches out, touching the outline, feeling its heat. He moans softly, pushing against her hand. She unzips him, revealing his throbbing erection, and tentatively licks the tip. He gasps, and she takes him into her mouth, sucking eagerly. He can't hold back, grabbing her head and fucking her face. She gags but keeps going, her pussy dripping with excitement.