The allure of confined public spaces for erotic activities lies in the thrill of engaging in taboo behavior while remaining discreet. The risk of getting caught adds to the excitement, and the adrenaline rush heightens the intensity of the experience. Additionally, the idea of doing something sexually adventurous in a public setting can be a major turn-on for some individuals. The limited space also makes the participants get creative with their movements and positions, adding a new level of intimacy and intensity.