Studies among BDSM practitioners in the US have shown that about half of all men find the idea of bondage to be erotic; many women do as well. The resulting consent and understanding is occasionally summarized in a written contract, which is an agreement of what can and cannot take place. Sadomasochism refers to the aspects of BDSM surrounding the exchange of physical or emotional pain. Some men enjoy masturbating during pegging. Works in this genre may explore philosophical, political or social issues. Reality and voyeur pornography, animated videos, and legally prohibited acts also influence the classification of pornography. The queening stool is also related to a smotherbox, which also allows the person under the lesbian milfs seat to be locked in place, restrained by the neck as in a set of stocks. Lesbianism in erotica deals with depictions in the visual arts of lesbianism, which is the expression of female-to-female sexuality. A spanking may be carried out with the use of a bare or gloved hand, or with any of a variety of implements, including a paddle, strap, hairbrush, feather duster or belt. Internationally, hentai is a catch-all young gay porn term to describe a genre of anime and manga pornography. Whether or not licking and fondling is considered tea bagging was once debated on the Howard Stern Show. It is typically animated pornography, as the legal age to be featured in a pornographic film in Japan is 18. The most common male masturbation technique is simply to hold the penis with a loose fist and then to move the hand up and down the shaft. Those with diaper-related gay hentai paraphilias differ widely in their focus of attention. Works in this genre may be considered adult for any number of reasons. The consensual submission of the submissive is sometimes demonstrated to others by symbols indicating his/her belonging to the dominant, such as wearing a collar, special tattoos, piercings, a very short haircut or a bald head. These include gently sucking and tugging on the scrotum and use of lips to ensure minimal contact with their teeth.