The evolution of 晒 (shài) perfectly mirrors the changes in modern Chinese society. Literally, its importance is rooted in the daily necessities of life. In many parts of China, people still commonly dry laundry, preserved meats, and grains in the sun. The act of 晒被子 (shài bèizi), or airing out one's comforter in the sun, is a common and comforting household ritual believed to kill mites and freshen the bedding. Figuratively, the rise of 晒 as slang is inextricably linked to the explosion of social media platforms like 微博 (Wēibó) and especially 微信朋友圈 (Wēixìn Péngyǒuquān - WeChat Moments). In this context, “shài-ing” is the act of sharing personal life updates. This differs from the Western concept of “flexing” or “showing off.” While “flexing” often carries a negative connotation of arrogant bragging, 晒 (shài) can be much more neutral or even positive. It often simply means “to share one's joy.” For example, friends might excitedly encourage you to 晒 your vacation photos. It taps into a collectivist cultural value where sharing personal happiness with your “circle of friends” is seen as a way to include them in your life. Of course, if done excessively or with materialistic intent (e.g., constantly posting luxury goods), it will be perceived negatively as bragging, or 炫耀 (xuànyào).
晒 (shài) is used constantly in both spoken and digital Chinese.
This usage is straightforward and refers to the sun.
This is the most common usage among younger generations. It's almost always followed by the object being “shown off.”