"Swingballs" is a play on the term "swingers," referring to couples or individuals who engage in sexual activities with other couples as a recreational or lifestyle choice. The term "swingballs" adds a slight twist by incorporating the concept of sports and games, possibly suggesting that the act involves some form of physical activity or interaction. In this context, it can be used as a tag for porn content featuring swingers or people engaging in partner swapping activities.