[afraidfortherepublic]

... worked on the "through" practice with a few big cardboard boxes taped together with a blue tarp draped over the end of it and taped on...

Good suggestion! Thanks.

[HairOfTheDog]

Start out with the tarp just barely hanging to the ground at first, so he can push right through it, and then gradually pull it out longer till it is like the real ones he has to burrow through..