When my kids were young, I taught them that guns were dangerous but not secrets. If they wanted to touch one, all they had to do was ask. I lived in the country so I took them out to my personal range and shot with them around. I invited them to shoot, they rarely took me up on the offer, but the offer was ALWAYS on the table. If they asked about the guns, I made a point to drop what I was doing and show, shoot, etc whatever they wanted.
Education is the key. Locking up the gun or hiding it does not remove the curiosity. Unless you lock the gun up 100% of the time they are around, EVENTUALLY they will get a hold of the gun. They MUST understand it is not a toy or some sort of fascinating, taboo object. That is too tempting to kids.
In life, strive to take the high road....It offers a better field of fire.
"Robo is right" Fuzzball