The Blessings of Maa Baglamukhi produce a divine protective shield in the form of the aura all over somebody thereby guarding him/her from malefic energies in the form of black magic spells or evil eye. Another etymology suggests that valga signifies "to paralyze" and symbolizes the strength of stambhana, "paralysis" https://www.youtube.com/shorts/5VeSyP9JRw0