Shiva Purana
यथाशोभं प्रकुर्वीत श्लक्ष्णमिष्टं मृदा स्थिरम् ॥ अश्वत्थपत्रवद्योनिं गजाधारवदेव वा ॥ ७ ॥
The soil should be smooth, desirable and stable according to its beauty. The vagina is like a peach leaf or like the base of an elephant.
english translation
yathAzobhaM prakurvIta zlakSNamiSTaM mRdA sthiram ॥ azvatthapatravadyoniM gajAdhAravadeva vA ॥ 7 ॥
hk transliteration by Sanscript