How Can The Holy Spirit Fit Inside You?

Last night was a stormy and beautiful night. After dinner I brought my older sons outside to enjoy the storm, stargaze, and cuddle. The wind was strong, my sons had never seen and felt such strong winds. I used this moment to, following John 3:8, teach my sons that God's Spirit is like the wind.This led to a series of great questions from Cru, my four-year-old and a new believer. I'm finding that some of the best sharpening of my theology comes from discipling my four-year-old and fielding his questions. Here is best question from last night:

Dad, how can the Holy Spirit fit inside me, I'm too small for him?

That's a good question. How would you answer it?