Open sex status screen and click on Giovanna to cycle between her and Hinata and Nami using the direction buttons. I had the same problem until I experimented with the menus.
I play it on my phone and there are no control buttons, just two finger taps to open and close the menu and tap anywhere to move Giovanna
This might be something the dev will have to work on.
Maybe this is a bug in the game, I don't know.
