Śrīmad-Bhāgavatam · Text 3.6.19
Who is speaking and story frame
मेढ्रं तस्य विनिर्भिन्नं स्वधिष्ण्यं क उपाविशत् ।
रेतसांशेन येनासावानन्दं प्रतिपद्यते ॥ १९ ॥
meḍhraṁ tasya vinirbhinnaṁ
sva-dhiṣṇyaṁ ka upāviśat
retasāṁśena yenāsāv
ānandaṁ pratipadyate
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.
Read this verse on Vedabase.ioThis verse has no purport; its meaning is explained by the verses around it.