洋葱少年暖我心薄荷少女冷只夏
[yáng cōng shăo nián nuăn wŏ xīn bó hé shăo nǚ lĕng zhĭ xià]
This poetic username combines elements suggesting warmth provided by an affectionate young man (like onions which can make one emotional), versus coolness experienced due to an aloof young girl who is described using mint imagery. Together they form contrasts that are especially vivid in summer ('only in the heat'), painting an interesting dynamic relationship scenario.