>>31649905She does it to keep Miko in line.
When Susei open mouth kissed Miko in front of Pekora, when Susei beat and embarrassed Miko infront of the fans, when Suisei tells Miko she is lucky to have Suisei and then Suisei forces her to watch as she has sex with other girls it's all a power move to ensure Miko k ows her place.
