Large appealing rump and thighs, usually thick and shines from fresh lotion.
Term comes from way back in the day of visiting your favorite Aunties house for a large family dinner. Seeing the Candy Yams glissining in the light and can't waiting to get your hands on them.

Itz what me n muh nigguhz eat allllla time

When using a porta-john that is in desperate need of servicing, your yam bag dips in the shit water when you sit down and gets a nice blue/brown coating.

The act of releasing on a girls chest.

When you put your special glaze on her booty after doggystyle

When a turd comes out so slick you barely feel it but so dense it won't flush.