Special jump attack in Mario and Luigi: RPG 2.

What's the control commands where the grown-up Mario or Luigi do the jump attack first and the baby versions next at the same time?

The baby attacks first and then the grown up. First you attack with A or B.(A= Mario and B= Luigi) Then you press X or Y (X= baby Mario and Y is baby Luigi) to let the baby attack. When the baby has attacked, you'll see the grown-up version come down and you press A or B