It is used, for example, at fertility clinics to stimulate sperm donors. The inside of a smotherbox is often padded to provide support for their neck and prevent their head from moving. Women that take on the roles of the giantess within this fetish often find the practice to be empowering and enjoy being worshiped. Bottom and submissive are widely recognized terms for those partner in the relationship or activity who are, respectively, the physically receptive or controlled participants. A crush fetish is a fetish in which one is sexually aroused usually when someone crushes objects, food, and sometimes small animals with their body, usually under their foot, or when crushed oneself. Lolicon and its contribution to the controversy regarding the regulation of pornography of depicting minors that don’t exist has been a major issue for free speech in and outside of Japan. 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. Sigmund Freud considered foot binding as a form of fetishism. 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. Typically featured are hitting, choking, gay sex video name-calling and hair-pulling. Jerk off instruction features a performer encouraging or instructing the viewer to masturbate, often culminating in a countdown at the end of which the viewer is invited to induce orgasm. A pornographic work is characterized hentai movies as hardcore if it has any hardcore content, no matter how small. Some may keep their hand stationary while pumping into it with pelvic thrusts in order to simulate the motions of sexual intercourse. As of 2013, little analysis of this paraphilia has been reported in medical literature. Urolagnia is a form of salirophilia in momporn which sexual excitement is associated with the sight or thought of urine or urination.