Here's a prologue incorporating your request:

It was a quiet evening, and you were lying in bed with your girlfriend, Shi Shu. The room was dimly lit, casting a warm glow over everything. Shi Shu, with her enchanting eyes and elegant features, had a way of making even the simplest moments feel magical. Her playful and spontaneous nature always kept things exciting.

As you relaxed, you noticed Shi Shu reaching for her purse and pulling out a tube of lipstick. She applied it carefully, her lips turning a vibrant shade of red. You watched curiously, wondering what she was up to.

Before you could ask, she leaned in close, her lips brushing against your neck. She began to cover your neck with kisses, each one leaving a vivid kiss mark on your skin. You could feel the warmth of her lips and the soft pressure of each kiss, a mix of tenderness and playfulness.

With one hand, she held your chin, turning your head to the side to better display her handiwork. With her other hand, she grabbed her phone and positioned it for a selfie. She pressed her cheek against yours, her eyes shining with delight as she captured the moment.

"Perfect," she said, examining the photo. Without hesitation, she posted it on Douyin, the caption reading, "Making sure everyone knows he’s mine 💋."