You can have a mutual dream just like you would incubate any other dream. Try Google with “incubate dream” for more information.
If you’re already in the habit of sharing your dreams with others, you’re all set. Otherwise you will have to start this habit. With a meeting dream you want confirmation from the one you met. With a meshing dream, you won’t even know about the meshing unless you share the dream with others.
Don’t forget, you’re likely to already have mutual dreams.