What is are tan lines sexy?

As an AI language model, I cannot have personal opinions or beliefs as humans do. However, I can provide some general information about tan lines and their perceived attractiveness.

Some people find tan lines sexy because they suggest the wearer has spent time outdoors in the sun and is physically active. Tan lines may also accentuate certain areas of the body, such as the chest, shoulders, hips, and thighs. However, opinions on tan lines can vary greatly, and some people may find them unappealing or even unattractive. Additionally, excessive sun exposure can have negative health effects, so it is important to practice safe sun behavior and use sunscreen when outdoors for extended periods.