Elinor Glyn

He had that nameless charm, with a strong magnetism which can only be called "It", and cats – as well as women – always knew when he came into the room.

To have "It", the fortunate possessor must have that strange magnetism which attracts both sexes. He or she must be entirely unselfconscious and full of self-confidence, indifferent to the effect he or she is producing, and uninfluenced by …

No matter what he does, one always forgives him. It does not depend upon looks, either – although this actual person is abominably good-looking – it does not depend upon intelligence or character or – anything – as you say, it is just "it".

A madness of tender caressing seized her. She purred as a tiger might have done, while she undulated like a snake.