Maybe more than a mantra, or trigger move, you should rethink how you approach the tasks you described.
Offensive intent would include moving towards the next turn from the fall line of the current turn. By beginning to set up that early you will be ready for the new turn by the time you reach the end of the current turn. That doesn't mean you do not finish the current turn though. Most of your speed control should come from route selection and finishing your turns is a large part of that.
Here's an idea that might help you. Speed control depends on two factors, route and the amount of braking you use. On an open slope you can choose your route and skiing round smooth turns is an easier option than trying to do so in the trees. So it comes down to tactical decision making, choose the tactic that best suits the terrain.
In addition you need to revisit how you get from one set of edges to the next. Hard edging late keeps your body inside the turn when it should be migrating back to neutral. Try adding more edging (tipping) and pressure near the middle of the turn instead of waiting so late to "work" the ski. Then try moving towards finishing the turn on a flat ski (releasing the turn by reducing the edge angle instead of unweighting the skis).
Remember that on ice there is only so much edge purchase we can produce and late in the turn all of the forces are trying to pull you sideways (down the hill). Chatter and skidding happen as a result of overwhelming our connection to the snow at that point. So instead of trying to add edge and pressure at that point, we need to think about absorbing some of that pressure and reducing the edge angle. An added benefit is that it also allows you to keep the torso moving towards the next turn instead of it remaining stuck in the last turn.