Two water signs read each other without words: intuition, emotional memory, an intimacy few bonds reach. You also catch each other's moods dangerously easily. Your work: don't drown together — someone has to remember to open the window.
One launches (cardinal), the other adapts (mutable): natural flexibility — few head-on collisions. Just don't let direction always come from the same person; the mutable one needs to be heard too.