SB 3.6.19
Devanāgarī
मेढ्रं तस्य विनिर्भिन्नं स्वधिष्ण्यं क उपाविशत् । रेतसांशेन येनासावानन्दं प्रतिपद्यते ॥ १९ ॥
Text
meḍhraṁ tasya vinirbhinnaṁ sva-dhiṣṇyaṁ ka upāviśat retasāṁśena yenāsāv ānandaṁ pratipadyate
Synonyms
meḍhram—genitals;tasya—of the gigantic form;vinirbhinnam—being separated;sva-dhiṣṇyam—own position;kaḥ—Brahmā, the original living creature;upāviśat—entered;retasāaṁśena—with the part of the semen;yena—by which;asau—the living entity;ānandam—sex pleasure;pratipadyate—experiences.
Translation
When the genitals of the gigantic form separately became manifest, then Prajāpati, the original living creature, entered into them with his partial semen, and thus the living entities can enjoy sex pleasure.