The ingredient in this is a peculiar contact between the organ of sense and its object, and the consciousness of pleasure which arises from that contact is called Kama.
Kama is to be learnt from the Kama Sutra (aphorisms on love) and from the practice of citizens.
When all the three, viz., Dharma, Artha, and Kama come together, the former is better than the one which follows it, _i.e._, Dharma is better than Artha, and Artha is better than Kama.

But Artha should be always first practised by the king, for the livelihood of men is to be obtained from it only.

Again, Kama being the occupation of public women, they should prefer it to the other two, and these are exceptions to the general rule.
_Objection 1._ Some learned men say that as Dharma is connected with things not belonging to this world, it is appropriately treated of in a book; and so also is Artha, because it is practised only by the application of proper means, and a knowledge of those means can only be obtained by study and from books.

But Kama being a thing which is practised even by the brute creation, and which is to be found everywhere, does not want any work on the subject.
_Answer._ This is not so.

Sexual intercourse being a thing dependent on man and woman requires the application of proper means by them, and those means are to be learnt from the Kama Shastra.