Containment is a way of putting things away after digging them up. I do it as a part of visualization. For example you can put it in a secure box that's padlocked and hidden far, far away on another planet. During the visualization you would picture going to the other planet on a space ship, landing on the planet, finding the box, opening it up, putting the memories inside, locking the box with 10 locks, burying it, getting back on the space ship, and flying back to earth. Only you know how to access the box of memories again and they are safely hidden far, far away. They can't hurt you if they are securely locked away. Then during your next session you do the reverse, traveling to the planet to open the box. You can hide the memories anywhere that feels safe to you, anywhere you desire.
I've done these kinds of exercises and they really help.