How to get baby after they wake from a nap?

Baby is 4.5 mo, he usually contact naps so I'm always right the when he wakes. Today I put my baby down and he stayed asleep. He just woke up happy, and this might sound like a stupid question but... How do you go and get them from a nap? Do you leave them while they are happy and wait for them to fuss/cry? Currently hiding from LO until he fusses hoping it will help him in someway.