The blessings of Maa Baglamukhi create a divine protective shield in the shape of an aura all around somebody thus shielding him/her from malefic energies in the form of black magic spells or evil eye. A further etymology implies that valga signifies "to paralyze" and symbolizes the strength of stambhana, https://www.youtube.com/shorts/5VeSyP9JRw0