To answer a few questions:
"Do they do that by themselves, or is there some coaching involved?"
Dozer and Digger were up there already, but Dudley couldn't get his rear off the ground, so I gave him a boost.
"..maybe they all like being squished together."
Dozer had enough just after I took the pictures. He doesn't like to be bothered when sleeping.
"I'd be interested in knowing the pieces/parts you used to make it!"
I spent $110 all together, $50 for pipe & fittings, $60 for the large pillows (walmart), and I had the plywood on hand, so no added cost for it. I just cut to fit the pillows I bought, no plans. I build stuff like that all the time. I go buy a bunch of pieces and just start sticking things together until it fits. :lol:
Here's a few pictures of the frame work: