In discussing the process with the actors, I made it clear to them that they could improvise but that the sum total of their improvisation needed to impart certain plot points, and schematic material.
Normal kids in their teens want to go and date girls and do mischievous things, your hormones are jumping around, but I stayed in my bedroom in search of something.
One of the greatest joys of tennis is having a nice volley and not really keeping score, not really looking at the lines, but just catching up with each other.