夜空中最亮的电灯泡
[yè kōng zhōng zuì liàng de diàn dēng pào]
Literally means 'The brightest light bulb in the night sky.' It humorously implies being a 'third wheel' or feeling overly conspicuous and out of place like a bright light amidst the subtle starlight, often carrying a tone of awkwardness in romantic social settings.