Scientists argue that the concept of the norm in psychology does not exist. Each person has their own box, which he considers acceptable. Moral and ethical norms established in the community, are also quite different for certain crops. The boundaries of the permissible constantly expanding. In any newsagent sold openly erotic literature. Magazines are full of suggestions about intimate acquaintances. Homosexuality is discussed openly. In some countries even allowed same-sex marriages, they are allowed to have children.
Can be called perverse sexual behavior in which a person cares only about satisfying their own sexual desires and needs. It simply uses the partner, not caring about his feelings and state of mind. Can be considered as a perversion of violence. Of course, if we are not talking about voluntary masochism.
As for other sexual practices, then there is nothing vicious. If people are satisfied with the relationship, and they enter into an agreement for them, it's a private matter. But talking about their secret desires, be careful. Partner can not take your fantasies. The sexual sphere - this is a very delicate matter, and your testimony may even shock the second half. Offering new options, do it carefully, a preliminary test.
If you are faced with a situation for you is totally unacceptable, you better get away from this man. You can not change the partner, to persuade him. This seductive illusion. Sexual preferences are formed during adolescence, when sexual energy is so great that it is directed in all directions and can move in any direction. Later preferences in sex is not modifiable. Cure sexual perversion, violations of curvature sexual orientations impossible. Only sexologist can teach implement unusual desires, without entering into conflict with the culture and the law.