After you connect them, and activate the heart icon on each, they will both begin to dance back and forth to a tune. Now press the B (middle) button (on one or both, I don't remember.) They should stop dancing, the tune should become a long solid beep and the characters will slide off-screen. A moment later if they slide back on-screen with "OK" beside them, they're ready to mate. Now press the B (middle) button again (on both I think.) The tune will start again, and the screens will fill in all black. Then they will reappear and start dancing again. The whole process takes a long time (almost 3 minutes from the time you first connect them until the babies are born, etc.) Don't allow them to come apart during this time, or the whole process will stop and you'll have to start over.