How do you use the word infantile in a sentence?

He manages to behave like an adult at work, but in his personal life he is utterly infantile, and his wife enables the behavior by cleaning up all of his messes and waiting on him hand and foot.

Your average criminal is completely infantile, in the sense that he demands immediate gratification for all his wants and needs, and he throws a violent temper tantrum if anyone gets in his way.

SIDS is still one of the most common causes of infantiledeath, yet doctors still really don't know why or how it happens.