Sing songs like wheels on the bus and excercise their bodies... Like crossing arms across their midline... Making faces in the mirror and just cuddling. Pinterst has some great ideas but 4 month olds are still very young and kinda boring... They mostly just love having mommy's attention!
As tired as i am i try to give my daughter as much attention as possible because they need the stimulation and bonding but ill leave her be to play alone maybe 10 mins time max. Im 30 weeks 4 days and my daughter is 1.
My daughter will be 7 months tomorrow and ill be 14 weeks Friday. I know how you feel. But Bella just really plays by herself in her exer saucer or plays with her bottle