A relatively big size for a woman. But there are many types of
dd, so dd being one size and only one size in particular is incorrect.
A
dd cup is a size of breasts in which the typical difference between the under-bust and the over-bust is 5 inches/12.7 cm.
A dd cup is perfectly fine and okay-looking to any size. There is nothing bad if a dd cup on any body type looks too big or too small. unlike mister 9inchdickman said.
If you think one dd cup woman's breasts are saggy and have
stretch marks, and immediately assume that all dd cup ladies' breasts are saggy and have stretch marks, then you might need to get more bitches and touch grass than just whine about other ladies'
breast size online. I for one, do have dd cups, and mine aren't saggy nor have stretch marks.