Depending on the context you need this text for, here are a few ways it is generally applied:
The phrase is a common search term used in online adult entertainment and photography circles to describe a specific demographic of women—typically those in their 30s or older with a larger bust size. busty over 30
Users may use it as a self-descriptive hashtag or bio line to attract a specific audience interested in that body type and age range. Depending on the context you need this text
It serves as a SEO (Search Engine Optimization) keyword for websites like AnySmut to categorize galleries featuring mature women. busty over 30