Kamasutra 2.6.17

2.6.17

sa dvividhaḥ --- pārśvasaṃpuṭa uttānasaṃpuṭaś ca/ tathā karmayogāt/

When the legs of both the male and the female are stretched straight out over each other, it is called the "clasping position.". It is of two kinds, the side position and the supine position, according to the way in which they lie down. In the side position the male should invariably lie on his left side, and cause the woman to lie on her right side, and this rule is to be observed in lying down with all kinds of women.