SB 9.18.31

vilokyauśanasīṁ rājañ
 charmiṣṭhā suprajāṁ kvacit
tam eva vavre rahasi
 sakhyāḥ patim ṛtau satī
Word for word: 
vilokya — by seeing; auśanasīm — Devayānī, the daughter of Śukrācārya; rājan — O King Parīkṣit; śarmiṣṭhā — the daughter of Vṛṣaparvā; su-prajām — possessing nice children; kvacit — at some time; tam — him (King Yayāti); eva — indeed; vavre — requested; rahasi — in a secluded place; sakhyāḥ — of her friend; patim — the husband; ṛtau — at the appropriate time; satī — being in that position.
Translation: 
O King Parīkṣit, upon seeing Devayānī with a nice son, Śarmiṣṭhā once approached King Yayāti at the appropriate time for conception. In a secluded place, she requested the King, the husband of her friend Devayānī, to enable her to have a son also.