What I have seen is this:
All plegdes get a pledge dad in thier chapter who is a brother they know the best, and they are mutually selected. then, the pledge dad gets one of his gal pals who is ina sorority to be the pledge's 'mom.' basically it is a party one night that they have, the pledge recieves a a cup and a bucket and a t shirt from the mom, and the pledge gets his mom a flower and (i think) a shirt. thats how they do it from what ive seen anyway!
I wanna be a pledge mom when im in a sorority!!!!