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. Lolita pornography gay bear porn caters to ephebophiles. Women with women Main article: Lesbianism in erotica: Lesbianism in contemporary mature milfs pornography Lesbian or girl-girl pornography features women engaged in sex together, but is typically aimed at a male audience. Yaoi is anime or manga that features gay males . A study of 164 males in Finland from two SM clubs found that 18.2% had engaged in coprophilia; 3% as a sadist, 6.1% as a masochist, and 9.1% as both. 18% of heterosexuals and 17% of homosexuals in the study pool had tried coprophilia, showing no statistically significant difference between heterosexuals and homosexuals. Additionally, the buttocks give an indication of the shape and size of the pelvis, which impacts reproductive capability. While wearing diapers, a diaper fetishist generally experiences a comforting feeling. This type of pornography is almost exclusively hentai, as true hermaphroditic humans are not fertile and are not usually found in nature. Clothed male, naked female is one-sided female nudity in which one or more females are nude while one or more men are clothed. The term bondage hentai videos describes the practice of Physical restraining. In humans, females generally have more round and voluptuous buttocks, caused by estrogen that encourages the body to store fat in the buttocks, hips, and thighs. While some fantasize about a giantess who is slightly taller than himself, others are interested in giantesses that are hundreds or even thousands of feet tall. Erotic spankings are commonly combined with other forms of sexual foreplay. The cover can have hinges or be a separate part. As women, they face concerns separate from men. These actors often play the top roles but this is not always the case, such as with Kristen Bjorn and some Bel Ami models.