一辈子做你的男孩一辈子做你的女孩
[yī bèi zi zuò nĭ de nán hái yī bèi zi zuò nĭ de nǚ hái]
Meaning 'be your boy forever / be your girl forever,' this username speaks to a deep wish for eternal youth and timelessness in one's role within an important relationship - emphasizing permanence and the desire not just to grow old together but also never lose the essence that makes their dynamic unique at its inception.