前凸后俏你很漂亮
[qián tū hòu qiào nĭ hĕn piāo liàng]
This username is a compliment to someone's attractiveness, describing them as having an attractive figure ('前凸后俏' refers to body curves) and directly telling the person 'you are very pretty'. It implies that the person has a good shape and appearance, especially emphasizing a beautiful figure.