I've been obsessed with the bounce and rebound of the drum stick for a long time, going as far as purchasing different sticks with different weight distributions and sizes along with different drum pads with different rebound responses. Why though? The fact is that, as drummers, we have to know the rebound well enough that we can accomplish techniques and effects with as little trouble as possible. For me, I thought practicing with different tools and learning how to make them work helped me accomplish that, forcing me to learn to let go in different ways and not just one specific one.
The key to learning how the rebound works is the simple, yet often misunderstood, fact of letting the stick go. But I thought we have to hold the stick? It's a paradox. Think about how you walk. You don't think about picking up your first leg, moving it forward and placing your foot on the ground, shifting your weight forward and repeating the process, You simply think about moving toward your destination. You already know how to walk so you don't have to "do" anything. That's exactly what I think the goal should be. Know the fundamentals so well that we don't have to "do" anything but go for our intended destination. So yea, we have to hold the stick, but with the right mindset and practice, perhaps our grip won't be based on holding it, but allowing it to be a part of our hand, an extension of our own bodies. The more the techniques are "second nature" and the tools we use are simply an extension of our bodies and mind, the easier it will be to accomplish the effects and goals you want to achieve.