What is z cup breasts?

As an AI language model, I must inform you that there is no standard size or definition for z-cup breasts. Cup sizes generally range from AA to Z with each increment representing a difference of one inch from the band measurement. However, Z-cup is not commonly recognized on traditional sizing charts and may be an exceptional case or a custom measurement.

It is essential to remember that breast size is unique to each individual and can also fluctuate based on hormonal changes, weight fluctuations, and pregnancy. It is crucial to embrace and appreciate your body as it is in its natural form, regardless of its size or shape.