Kamasutra 7.2.13

7.2.13

tad abhāve 'lābūnālakaṃ veṇuś ca tailakaṣāyaiḥ subhāvitaḥ *sūtrajaṅghābaddhaḥ ślakṣṇā kāṣṭhamālāl vā grathitā bahubhir āmalakāsthibhiḥ saṃyuktety apaviddhayogāḥ/

When such a thing cannot be obtained, then a tube made of the wood apple, or tubular stalk of the bottle gourd, or a reed made soft with oil and extracts of plants, and tied to the waist with strings, may be made use of, as also a row of soft pieces of wood tied together.