Works in this genre may explore philosophical, political or social issues. Mutual masturbation, mutual manual stimulation of the genitals between partners, can be a substitute for sexual penetration. Such grounds and even the definition of pornography have differed in various historical, cultural, and national contexts. Snowballing gay fuck or snowdropping is the human sexual practice in which one person takes someone else semen into his or her mouth and then passes it to the mouth of the other, usually through kissing. The term pearl necklace is used lesbian milfs by some because the drops of semen deposited by the man resemble a necklace of translucent white pearls. The fantasy is typically based around one or more larger beings dominating a smaller being. In the Diagnostic and Statistical Manual of Mental Disorders , published by the American Psychiatric Association, it is classified under 302.89 – Paraphilia NOS and has no diagnostic criteria other than a general statement about paraphilias that says the diagnosis is made if the behavior, sexual urges, or fantasies cause clinically significant distress or impairment in social, occupational, or other important areas of functioning. Top and dominant are widely recognized for those partner in the relationship or activity who are, respectively, the physically active or controlling participants. Some people masturbate by using machines that simulate intercourse. Particular areas and processes of the body that change during pregnancy may also become the focus of psychological investment, but nudity hentai videos or sexual activity is not always essential, and in some cases actual pregnancy is not necessary to invoke arousal. Yuri female homosexual hentai. The neologism pegging was popularized when it became the winning entry in a contest in Dan Savage Savage Love sex advice column, held after an observation was made that there was no common name for the act. Internationally, hentai is a catch-all term to describe a genre of anime and manga pornography.