Recorded in Feng Menglong's late-Ming story collection 《
醒世恒言》(Xǐngshì Héngyán, Stories to Awaken the World), Vol. 25: ‘
白长吉自挨进了身子,
无一日不来掇臀捧屁。’ The vivid disgust of the imagery — literally lifting someone's rear and praising their fart — is the whole point.