Introduction to the pornographic novel "The Vulgar" - I saw my sister naked, wearing only a lace-edged apron in front of her, lying on the combing table, with a big white butt raised. Behind her, a man was half squatting, spreading her sister's butt with both hands, burying her head between her legs, and licking her pussy violently. The head was shaking behind her butt, and she looked like she was licking very hard.