Like people have suggested before, it's probably a mental block that's keeping your body from following your brain. Being comfortable and in control when on your board is something that just comes from experience, so there may unfortunately not be a "trick" to fixing this. However, there are definitely ways to train and speed things up. Most skaters are either "frontside skaters" or "backside skaters", meaning that they feel more comfortable turning one way over the other. You are likely a frontside guy, so maybe you can compensate this involuntary motion by doing lots of backside stuff. Find some transition and try carving and kickturning backside a lot. Maybe give backside 180s or reverts on flat a try.