Parshaman: That’s actually the answer to the following stira in the megillah:
It says at the beginning Vachamaso Bo’aro Vo, meaning that Achashverosh’s shvigger’s name was Bo’aro Vo.
Later on, the Megillah says that Vachamas Hamelech Shochochoh, meaning that Achashverosh’s shvigger’s name was Shochochoh.
Teretz is…. Vashti Hamalka Asisa Mishtei Nashim, as you said 🙂