Adult Book Store. Usually its one with a video booth area and/or a "cinema" where people go to hang out and engage in various activities with similar minded people ranging from exhibitionism/voyeurism, semi-public masturbation, sex with relative strangers, some form of group sex/activity, glory holes and so on. Many people will use it as a no strings attached compartmentalized vacation from their normal life to let loose and indulge kinks/fetishes then go back to daily life without having to deal with any relationships or or having their sexual interests invade on professional/family life