Snowballing 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. This makes varying degrees of stimulation an integral part of oral sex for many men. Concerted deployed sexual rejection exercised on the partner can be an aspect of Dominance and Submission as well. Many fantasies include the macrophile shrinking before a normal sized woman or keeping his or her normal height while the partner grows in size. 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. Sometimes one or more fingers may be inserted into the vagina to stroke its frontal wall where the G-spot may be located. Rape pornography features performers simulating rape. At the end of the evening the female partners would randomly select keys from the bowl and leave with that key owner. The term bondage describes the practice of Physical restraining. Among swinging couples, one of the two partners is often the driving force and the other is more passive-supportive of the addition of additional sex parties. In 1988, a hot gay sex sex tape caused significant damage to Rob Lowe career. Reality and voyeur pornography, animated videos, and legally prohibited acts also influence the classification of pornography. The term sadomasochism is derived from the words sadism and masochism naked milf . Tentacle erotica can be consensual, but frequently contains elements of non-consensual sex. Many cultures describe pain as an aphrodisiac. These actors often play the top roles but this is not always the case, such as with Kristen Bjorn and some Bel Ami models. Women with women Main article: Lesbianism in erotica: Lesbianism in contemporary pornography hentai videos Lesbian or girl-girl pornography features women engaged in sex together, but is typically aimed at a male audience.