Exploring himself

Anna

My 4 year old son has a sudden fascination with his penis. He is drawing it and is using quiet time to take his clothes of and explore his body. I heard this is a normal phase but i can’t not be traumatized by the process 😂. I dont know what is normal and what is not. I did not shame him and i keep repeating that these are his private parts and no one should see or touch what is under our underwear. But i really dont know if this a normal behavior and if i have to stop it or do what.