Kamasutra 2.10.15

2.10.15

saṃdarśanāt prabhṛty ubhayor api pravṛddharāgayoḥ prayatnakṛte samāgame pravāsapratyāgamane vā kalahaviyogayoge tad rāgavat//

(1) When a man and a woman, who have been in love with each other for some time, come together with great difficulty, or when one of the two returns from a journey, or is reconciled after having been separated on account of a quarrel, then congress is called the "loving congress." It is carried on according to the liking of the lovers, and as long as they choose.