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

Prudent readers will do well to hold Three Weeks at arm's length, unless they want to be cut by flying adjectives.

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 others. There must be physical attraction, but beauty is unnecessary.

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".