Agni said:
1-10. Ishall describe vows (to be practised) on the thirteenth day that gives all (things). Ishall describe Anangatrayodasi (the thirteenth day of God of love) that was done at first by the God of love. Lord Hara (Siva) (of the form of) God of loveshould be worshipped on the thirteenth day in the bright (fortnight) in (the month of) märgasirsa (December-January). Oneshould take honey in the night and do oblation with ghee, sesamum and unbroken rice. One who worships Yogeśvara (Lord of Yogas) (on the thirteenth day of the bright fortnight) in (the month of) pausa (January-February) after using sandal and offering oblations and one who worships Maheśvara (the great lord Siva) in (the month of) magha (February-March) (on a similar day) after using pearls would reach heaven. One who practises the vowshould take water and raven and worship (on a similar day) in (the month of) phålguna (March-April) and consume camphor and worship (lord Siva) of his own form in (the month of) chaitra (April-May). (By those) one would become fortunate. Oneshould worship Mahārūpa (the lord of the great form) in (the month of) vaišākha (May-June) eating fruits of nutmeg. One who practises vowshould worship (lord) Pradyumna (one of the five forms of Vishnu) on (a similar) day in (the month of) jyaistha (June-July) eating cloves. Oneshould worship the consort of Uma (Śiva) in (the month of) åshādha (July-August) taking sesamum water. Oneshould worship the bearer of trident in the hand (Śiva) in (the month of) Śrāvaņa (August-September) consuming fragrant water. (The practiser of vow)should worship Sadyojäta (one of the five forms of Siva) in (the month of) bhädrapada (September-October) consuming agallochum. Oneshould worship Indra (the lord of thirty-three celestials) in (the month of) asvina (October-November) taking gold (immersed) water. The person practising vowshould worship Vighneśvara (lord of obstacles, son of Siva) in (the month of) kārttika (November-December) eating madana. The golden (image of) Śivashould be covered with mango leaves and a cow (covered and) worshipped and bed, umbrella, pitcher, sandals and vessel for ediblesshould be given to a brahmin at the end of the year. Oneshould contemplate on (lord Siva) causing delight to Rati (wife of God of love) on the thirteenth day in the bright (fort-night) in (the month of) chaitra (April-May) andshould draw ashoka tree with red-lead and turmeric. One who seeks pleasureshould worship for a year and practice the vow of Kāmatrayodasi.
Summary of chapter 191 of the Agni Purāṇa is as follows:
Vratas on the thirteenth tithi are described, primarily involving Śiva in his Kāmadeva aspect. The Anaṅga-trayodaśī, originally performed by Manmatha himself after the destruction of his physical form, is observed on Mārgaśīrṣa-śukla-trayodaśī by worshipping Śiva as Kāmarūpa. The twelve monthly prescribed offerings cycle through madhu, mauktika-jala, kaṅkola, karpūra, jāti-phala, lavaṅga, tila-jala, su-gandha-jala, and suvarṇa-jala in sequence. The Kāma-trayodaśī on Caitra-śukla-trayodaśī involves marking an aśoka tree with sindhūra and worshipping Kāma flanked by Rati and Prīti for one year, granting the fulfilment of legitimate desires and the restoration of marital harmony.