Shiva Purana
आनन्दार्थं शिवस्तस्याः सुप्रसन्नश्च पार्थिवे ॥ तस्मिँल्लिंगे लयं यातः पूर्णांशेन तया हरः ॥ ३१॥
For her bliss, the delighted Śiva, vanished into that earthen phallic image along with her.
english translation
AnandArthaM zivastasyAH suprasannazca pArthive ॥ tasmi~lliMge layaM yAtaH pUrNAMzena tayA haraH ॥ 31॥
hk transliteration by Sanscript