Normal. I used to do this with my late doggie Blackie. People thought I was nuts for letting her sleep on the couches and beds, but she looked so cute on them. I still miss her.
Frankly I think that's sweet of you. It shows a deeper appreciation for the well-being of your beloved pets. I have six dogs so I assure you I understand this feeling.
One time I was house sitting for my mom and when I got into bed I felt her cat creep under the covers and completely hug my leg. It was actually pretty unnerving since I could feel its claws. It wouldn't move the whole night. How do animals breath under there?