The intimate act was meant for family life and for procreating,  that is its real purpose. One does not have to be an expert on the subject to realize this.

To look at promo etc is to perform the "intimate act" contrary to the way it was intended.  Like using a machine contrary to the way the manufacturer advises.

A person that uses an instrument in an incorrect manner, can expect trouble with it , so too if we look at promo we can expect trouble.

The manufacturer's instructions are the Torah and this type of activity is not permitted.

One should try to stop this when he can and be at peace with himself that he is taking care of this important part of himself.

The best way to go about it in my opinion is daily Torah study. As stated in the Talmud:

Talmud Kidushin 30b. Even so did the Holy One, blessed be He, speak unto Israel: ‘My children! I created the Evil Desire, but I [also] created the Torah, as its antidote; if you occupy yourselves with the Torah, you will not be delivered into his hand."