Do you mean 'pudding' without a 'g'? As a term of endearment?
I'm not sure where you found this word, but 'puddin' or (even pudding) is not a normal thing to call someone, regardless of their gender. The fact that you are girls doesn't make much difference. Addressing someone as 'pudding' suggests that they are fat, so it isn't a very nice thing to call someone. There may be some couples who have particular terms of endearment, and some may call each other 'pudding'.... or pumpkin, or cabbage...or anything else. But that doesn't mean that you should copy them!