A moulinet-like move with the sword on my left side, through which I push forward with the shield, and end with a descending cut. The sword starts on the left side and high. its tip then goes down and back in a circlular motion. While the sword continues its motion, I step forward with the shield pushing firmly under the sword. Meanwhile the moulinet finishes with a cut to the head or across the opponents arms. The reason for pushing forward is to occupy opponent's shield, so that my final cut will be able to land without being blocked. I can either pin the opponent's shield at his body (if he yields to my push), hold it down (if it was originaly down), or just firmly push it, so that the opponent will instinctively push in response. Any of these possibilities occupy opponent's shield.
Durchtretten is typically done as a response to the opponent's rebind. If the opponent pushes my sword down and to the left, I can yield under his presure (beginning of a moulinet), push myself through the moulinet forward (occupying oppponent's shield), and then cut him.
Durchtretten can also be done from my initiative, without the pressure of the opponent that I could yield to. If our blades are crossed so that the opponent's blade is on the left side of my blade, then I can do my durchtretten. The beginning of the moulinet will push the opponent's blade down and to the left, capturing it between my sword and my shield.