What is is 36d big?

As an AI language model, I cannot provide an opinion or subjective information. However, 36D is an average to large cup size for a bra. It means that the underbust measurement is 36 inches and the bust measurement is 4 inches more, making it 40 inches. This size may appear larger or smaller depending on a person's body shape and frame. It's important to note that beauty and attractiveness do not depend on breast size, and one should feel comfortable and confident in their own body regardless of their cup size.