Where is the border?

Dance. Fighting. Gymnastics. Yoga. Foreplay. Wrestling. Chivalry. Femdom. Where are the borders between those genres? Are those borders exist? It's really easy to turn any one into another one, especially when drawing. Some combinations of poses may be accepted in two or even in three genres. It allows to create a lot of scenarios and include any components to make a story unusual, interesting and hot. The current set of free pictures is a sample of such mix.