The Overhead Reverse Lunge.
In most circumstances, it’s best to teach the reverse lunge before the front lunge, as it’s a bit more joint friendly and a little easier to learn. Additionally, the reverse lunge targets the posterior chain (glutes & hammies) better than a forward lunge, and for most people, people lack muscle development in the ‘ol money maker.
Remember that the leg that moves back is the one with the kettlebell overhead. Also, keep that shoulder firm and stacked in the joint.