我是孩子气的宝宝我是大人心的爸爸
[wŏ shì hái zi qì de băo băo wŏ shì dà rén xīn de bà bà]
This nickname combines two contrasting personalities in one individual, highlighting both childlike qualities ('childish baby') and mature parental attributes ('adult's dad'). It reflects someone who values a balance of innocence and responsibility.