The blessings of Maa Baglamukhi make a divine protecting shield in the form of the aura all-around somebody thereby shielding him/her from malefic energies in the shape of black magic spells or evil eye. One more etymology indicates that valga implies "to paralyze" and symbolizes the power of stambhana, "paralysis" https://www.youtube.com/shorts/5VeSyP9JRw0