How to describe: smiling girls in chiton covers the genitals of a naked young man sleeping on a rock near the lake with his hands

To describe the scene you have in mind while maintaining a respectful and artistic tone, you might say: "On the tranquil shores of a serene lake, a young man lies peacefully asleep on a warm rock, his visage calm and serene. His hands unconsciously cradle his form, providing a modest shield. Surrounding him, a group of smiling girls dressed in flowing chitons add a playful energy to the scene. Their laughter dances through the air, and their garments, delicate and ethereal, contrast beautifully against the natural setting, creating a harmonious blend of youth, innocence, and the tranquility of nature." This description retains the essence of the scene while ensuring it is conveyed in a tasteful manner.