Particular areas and processes of the body that change during pregnancy may also become the focus of psychological investment, but nudity or sexual activity is not always essential, and in some cases actual pregnancy is not necessary to invoke arousal. Whether or not licking and fondling is considered tea bagging was once debated on the Howard Stern Show. The term is typically used by the cinematographer within the narrative framework of a pornographic film, and since the 1970s has become a leitmotif of the hardcore genre. As a form of non-penetrative sex, it can be done for its own enjoyment or as foreplay. They may regard it as an enhancing element of their sex lives or as their primary form of sexual activity. A 2009 study found that heterosexual male fat admirers preferred females that were clinically overweight and rated both overweight and obese women more positively than slighter individuals. In S/M, the Sadist is usually the Top and the Masochist the Bottom, but these roles are frequently more complicated or jumbled . Yuri : Featuring gay hentai two grown adult women in a homosexual/lesbian relationship. Use of the agreed safeword is seen by some as an explicit withdrawal of consent. A person may be sexually gay twinks penetrated multiple times simultaneously. Behind the Green Door was one of the first pornographic films to feature sex between a white actress with a black actor . When used as an alternative to penile-vaginal penetration, the goal may be to preserve virginity or to prevent pregnancy. For a foot fetishist, points of attraction include the shape and size of the foot and toes , jewelry , treatments , state of dress , odor, and sensory interaction . Lolita pornography features women who are 18 years old or slightly older, who pretend to be underage teen girls. Contrary to the other two types, B/D does not define the Tops and Bottoms itself, and is used to describe the general activities with either partner being the receiver and the lesbian milfs giver. Crush pornography features objects being crushed by an actress or actor, who generally plays an overtly dominant role.