The blessings of Maa Baglamukhi create a divine protective defend in the form of an aura around somebody thus guarding him/her from malefic energies in the shape of black magic spells or evil eye. One more etymology indicates that valga signifies "to paralyze" and symbolizes the power of stambhana, https://baglamukhi41738.tinyblogging.com/what-does-baglamukhi-mean-76323545