The Compendium of Caraka 8.9.60

8.9.60

netradīrghāṃ ghṛtābhyaktāṃ sukumārāmabhaṅgurām/
netravanmūtranāḍyāṃ tu pāyau cāṅguṣṭhasaṃmitām//

of the length of the pipe, smeared with ghee, delicate, and unbreakable,
into the urinary tube as with the pipe, and into the rectum measured like a thumb.