Stand facing the barbell while holding the end of the bar at your side with one hand.
With the leg on the same side of your body as the barbell, lunge backward and across your body at a 45 degree angle while keeping your weight on your front heel to lower your back knee gently to the ground.
Drive through your front heel as you step back to the starting position, and repeat for the desired number of reps before switching sides.
Landmine Curtsy Lunge Exercise Guide - Glutes Workout | MuscleWiki