A pornographic work is characterized as hardcore if it has any hardcore content, no matter how small. Kinbaku means tight binding Kinbaku-bi which literally means the beauty of tight binding. The reverse hentai sex of this, in which nude women interact with clothed men, is called Clothed male, naked female . Sadomasochism is practiced in isolation relatively rarely, though some masochists report biting, pinching, or even stun-gunning themselves as a prelude to, or as part of, masturbation. Hardcore pornography is pornography that depicts penetration or extreme fetish acts, or both. The concept of lesbian, to differentiate women with a shared sexual orientation, is a 20th-century construct. Other objects such as ball point pens and thermometers are sometimes used, although this practice can lead to injury and/or infection. People momsex may engage in anilingus for its own sake, before anal fingering or penetration, or as part of foreplay. It contains graphic sexual activity and visible penetration. Lolita pornography features women who are 18 years old or slightly older, who pretend to be underage teen girls. The current record is held by Lisa Sparks who had sex with 919 men on October 16, 2004 in Warsaw, Poland as part of the Third Annual World Gangbang Championship and Eroticon 2004. Gay-for-pay describes male or female actors, pornographic stars, or sex workers who self-identify as heterosexual but who are paid to act or perform as homosexual professionally. The phrase gay boy porn is commonly found on porn sites. Cuckolding can also be mixed with other non-monogamous relationship arrangements with which it has substantial overlap such as Swinging, wife-swapping, open relationships, and polyamory, etc. Sexual relations between women have been illustrated as well as narrated, but much of the written material from the early modern period has been destroyed. Comic books often featured characters being tied up and tying others up, particularly in damsel in distress plots. Women porn is often produced by women and aimed specifically at the female market - rejecting the view that men are turned on by porn but women only by a box of chocolates.