That is the question my son asked me. This was after he decided Easter should happen every day. (It was probably the gifts from the Easter Bunny, the great meal and the Easter Egg Hunt with his best friend that won him over). I tried to explain to him, Jesus does come every day. As Catholics, we believe he comes every day in the form of the Eucharist and he is present all around. I knew this was going to be a hard concept to explain to a three year old, half of adults don't understand this concept very well.
As he was processing, my son said, "does He come even on my birthday? Even during football season?," he asked excitedly. Yes, even when our team loses, I thought to myself with a smile. He pondered this for a while. "How do I talk to Jesus?" I showed him the picture of Jesus on our bedroom wall and said, "you can just talk to Him like He's here". "But He's not here!" he replied, "That's just a picture." I thought for a moment and said, "you know how you can talk to your grandparents on FaceTime and they can see and understand you but they aren't right in the room with you? You can talk to Jesus like that."
At least he's not at the age right now to point out that there's absolutely no reference in the Bible to FaceTime. I told him, "when Mommy and Daddy receive the Eucharist, we are able to receive Jesus and you will be able to when you are older too!" I'm not sure how he sorted everything out in his mind, but he went on to pray right in front of me, looking at the picture of the Sacred Heart of Jesus, the image my grandmother passed on to me with her devotion. I had faith that my son would sort it all out some day.