Walking on different surfaces can be count as socializing, but always when there is a chance to try something new, I address Miki to try it.
For example a metal staircase where you can see through the stairs into the ground, can be scary for some dogs, as it was for Miki at first. We also got a fun surface from the cardboard box that our new mattress arrived in.
And we did use this box as a fun tunnel as well.
