Vinaya Pitaka
Chinese "cebi" 廁箆 "toilet spatula" is first recorded in Buddhabhadra's (c. 419) "Mohe sengqi lü" 摩訶僧祇律 translation of the Mahāsāṃghika version "Vinaya Pitaka" monastic rules; the toilet etiquette section (明威儀法之一) says inside toilets should have privacy partitions, with "cebi" shit-sticks placed at the side.