卖萌少年撒娇少女
[mài méng shăo nián sā jiāo shăo nǚ]
The username combines 'cute' and 'playful,' with 'selling cute' referring to intentionally displaying childish or adorable behavior. Similarly, the latter part, involving '撒娇' means expressing oneself in a coquettishly endearing manner which can also have some playful connotations of flirting in Chinese culture, often associated with teenagers expressing their feelings.