Side-to-side Chin

Stand with your feet shoulder-width apart and your knees slightly bent.

Grasp a pull-up bar with an overhand grip, hands slightly wider than shoulder-width apart.

Hang from the bar with your arms fully extended and your body relaxed.

Pull yourself up by bending your elbows and bringing your chin towards the bar, while keeping your body straight.

Once your chin is above the bar, lower yourself back down to the starting position.

Repeat for the desired number of repetitions.

Losing tension in the core or lower back partway through the movement — because Side-to-side Chin loads multiple joints at once, a small breakdown in bracing at the hips or spine compounds through the whole chain.

Rounding the upper back or shrugging the shoulders up toward the ears at the start of the pull instead of initiating with the target muscle.

Rushing through reps using momentum rather than controlling both the lifting and lowering phase, which is especially important since there's no external load to force good tempo.

Skipping a warm-up set at lighter load/intensity — even "beginner" exercises benefit from a rehearsal set to groove the movement pattern before working sets.