Create a UserControl, and put your buttons on it.
When the first button is clicked, create an instance of your new control and set it's location to the top left of the button, show it, and call BringToFront:
Dim mc As MyControl = New MyControl()
mc.Location = MyButton.Location
When you want to get rid of it again, remove it from the Controls collection, then Close and Dispose the new Control instance.