How can I ask for my PlayStation 2 back from my cousin?

I was lending LENDING my Ps2 to my nine year old cousin, but my Aunt Donna asked my mom if they could keep it, and apperently my mom said yes, but I want to play kingdom hearts, and dance dance revolution 2, and all those good games that I loved. But, my cousin loves it, but my mom already told me that I couldn't get another one. And I don't have enough money to buy myself another one.So, how can I POLITELY ask my Aunt for my playstation back?