He was dutiful.

The altar boy dutifully followed the priest.

I wonder what ground cinnamon tastes like," said the King nonchalantly and put the spoon in his mouth. "Hmm? ...Shit! Water... water... in the fridge. Oh crap, no water in the fridge!" The King went on running around the room frantically, looking desperately for water. Luckily, Duke Onkled happened to be pouring himself a glass of water. "Your Omnipotence, have water," he offered dutifully. "Gimme!" demanded the King, then emptied the glass in a split second. "Damn, that was awful."

Layla was a dutiful caretaker.

I told Mary that I do not have time for a relationship because I have to focus on school," Tom said dutifully to his father. "I'm glad to hear that, my boy," he replied contentedly, patting his son on the shoulder. "There is enough time for such things later."

This girl was always good and dutiful.