Swapping has been widely used in Japan since the 1970s. It refers to sexual activity in which couples—married or otherwise in a romantic relationship—exchange partners. Swapping is a form of non-monogamy, typically involving multiple couples. Consent and mutual agreement are essential, and swapping should be distinguished from general orgies. Emotions such as jealousy and submission often intertwine, creating a unique kind of excitement and pleasure. While some may later feel regret, they rarely experience guilt. In Japan and many other countries, swapping is generally not subject to legal restrictions, yet it is often socially controversial. However, many couples engage in swapping to enhance both the quality and quantity of their sex lives, and for some, it serves as a way to deepen their relationship. Against this backdrop, swapping offers a new allure through the simultaneous sharing of voyeurism and sexual intercourse.