What is the X in X-mas?
in Sanskrit literature, a treatise on love and sexual technique
Sanskrit kama 'love' + sutra 'rule'
A detailed, erotic account of the art and techniques of love, possibly written by a first-century sage. An unexpurgated English translation was published in 1883 by the British explorer and scholar Sir Richard Francis Burton.
Note: Kama is the god of love in Hindu mythology.