The brother, with his massive cock straining against his pants, can't keep his eyes off his sister's big ass as she bends over to pick up a book. She catches him staring and smirks, "Like what you see?" He nods, his face flushing with desire. She turns around, hiking up her skirt to reveal her bare ass. "Then take it," she challenges. He doesn't need to be told twice, pushing his cock into her tight asshole and fucking her hard. She moans, her fingers rubbing her clit as he pounds her, their bodies slapping together in a symphony of lust.