Chandogya Upanishad (with commentary) · Chapter 2.13

ChUpBh_2,12.2 sa ya ityādi pūrvavat /
brahmavarcasī vṛttasvādhyāyanimittaṃ tejo brahmavartasam /
tejastu kevalaṃ tviḍbhāvaḥ /
annādo dīptāgniḥ /
na pratyaṅṅagnerabhimukho nā'cāmenna bhakṣayetkiñcinna niṣṭhīvecchleṣmanirasanaṃ ca na kuryāttadvratam //2//
iti chāndogyopaniṣadi dvitīyādhyāyasya dvādaśaḥ khaṇḍaḥ
=======================================================================
START ChUp 2,13.1
upamantrayate sa hiṅkāraḥ |
jñapayate sa prastāvaḥ |
striyā saha śete sa udgīthaḥ |
prati strīṃ saha śete sa pratihāraḥ |
kālaṃ gacchati tan nidhanam |
pāraṃ gacchati tan nidhanam |
etad vāmadevyaṃ mithune protam

ChUpBh_2,13.1 upamantrayate saṅketaṃ karoti prāthamyātsa hiṅkāraḥ /
jñapayate toṣayati sa prastāvaḥ /
sahaśayanamekaparyaṅkagamanaṃ sa udgīthaḥ śraiṣṭhyāt /
prati srīṃ śayanaṃ sriyā abhimukhībhāvaḥ sa pratihāraḥ /
kālaṃ gacchati maithunena pāraṃ samāptiṃ gacchati tannidhanametadvāmadevyaṃ mithune protam /
vāyvambumithunasambandhāt //1 //
START ChUp 2,13.2
sa ya evam etad vāmadevyaṃ mithune protaṃ veda |
mithunī bhavati |
mithunān mithunāt prajāyate |
sarvam āyur eti |
jyog jīvati |
mahān prajayā paśubhir bhavati |
mahān kīrtyā |
na kāṃcana pariharet |
tad vratam