Masturbation has been depicted in art since prehistoric times and is mentioned and discussed in very early writings. It may be used as foreplay, or as an alternative to sexual penetration. It can be combined with fellatio and the woman may move her breasts gaysex up and down on the penis for an additional stimulation, usually before the man reaches orgasm. Technically this is a form of exhibitionism rather than group sex per se. Jail/Prison/Police pornography involves people in police custody or inmates in jails or prisons in various sexual situations, such as strip searches or body cavity searches. Though the term anal sex most commonly means penile-anal penetration, sources sometimes use the term anal intercourse to refer exclusively to penile-anal penetration, and anal sex to refer to any form of anal sexual activity, especially between pairings as opposed to anal masturbation. Pornographic films are generally classified into sub-genres which describe the sexual fantasy which the film and actors mature milfs attempt to create. Strictly speaking, bondage means binding the partner by tying their appendages together; for example, by the use of handcuffs or by lashing their arms to an object. Can also include auto-fellatio, or performing oral sex on oneself. Sloppy seconds is a slang phrase for when a man has sexual intercourse with another person who already has received another man penis in the relevant orifice and is therefore wet or sloppy. The name of the practice, when it is done in a repeated in-and-out motion, is derived from its passing resemblance to the dipping of a tea bag into a cup of hot water as a method of brewing tea. Group sex can occur between people of all sexual orientations and genders. Using the term shemale for a transsexual woman often implies that she is working in the sex trade. Pornography is generally classified as either softcore or hardcore pornography. This is commonly called double anal or double stuffing. This is also hentai movies the case in many relationships not considering themselves as sadomasochistic; it is considered to be a part of BDSM if it is practiced purposefully.