If my memory serves me correctly, I tasted manga mappaas the first time at my Mom's sisters place. The mildly sour raw mangoes cooked in coconut milk was yum. I loved it so much that day, that everytime I visit her I would request her to make it for me. However, I have started trying my hand at this
Note: If you feel that the curry is not sour enough, you can add a little bit of Vinegar.