Install the pink crystal bed at your main campsite, cabin or inside your camper.
It works best with the cabin and camper because you can more directly control camera angle when taking a picture.
With a little camera angle technique, you can use it to take pictures that look like you're laying down on the floor in your camper!
Only the pink crystal bed works! The other (blue) crystal bed does not work! :O
I learned this from looking at pictures of Japanese players of Pocket Camp and then I found this Youtube video:
On Facebook I have the page Animal Crossing: Forever
https://www.facebook.com/pg/Animal-Crossing-Forever-1928637950714279/posts/?ref=page_internal