The blessings of Maa Baglamukhi create a divine protecting shield in the shape of the aura all-around somebody therefore guarding him/her from malefic energies in the shape of black magic spells or evil eye. Another etymology suggests that valga usually means "to paralyze" and symbolizes the power of stambhana, "paralysis" https://www.youtube.com/shorts/5VeSyP9JRw0