Again a dog is clean when he seizes a deer in hunting, though food touched by a dog is otherwise considered very unclean.

A bird is clean when it causes a fruit to fall from a tree by pecking at it, though things eaten by crows and other birds are considered unclean.
And the mouth of a woman is clean for kissing and such like things at the time of sexual intercourse.

Vatsyayana moreover thinks that in all these things connected with love, everybody should act according to the custom of his country, and his own inclination.
There are also the following verses on the subject.
"The male servants of some men carry on the mouth congress with their masters.

It is also practised by some citizens, who know each other well, among themselves.

Some women of the harem, when they are amorous, do the acts of the mouth on the yonis of one another, and some men do the same thing with women.