Tantrasara mentions the iconography with the goddess Bagulamukhi. It mentions that the goddess is seated on the golden throne floating inside the spectacular ocean. An additional etymology suggests that valga signifies "to paralyze" and symbolizes the power of stambhana, "paralysis" which the goddess is alleged to grant; this theory https://analsextoys48371.suomiblog.com/about-baglamukhi-48300864