She rests her front paws on the floor, while the back of her body remains on her chair. She stays that way for a long time. It seems to me, that she is heavy in her barrell, and has tiny little hips, in comparison. She is 18 months, and lean, active, and healthy.
My 9 yr. old lab has done this from the puppy stage. She loves to sit on my lap when I am sitting cross legged on the floor. She just like to elevate her rump a little. (Plus it makes it easier for me to pet her : : ;D
Fanny likes to sit on the steps like that, she surveys her territory. When outside, she barks her sorry story out to the neighborhood, until I open the door and tell her to get in, she barks one more time and then I say don't make me come out there and she takes one more look and then stands up with her front paws on the second step and her back on the top step and then comes running in. In the house she sits at the top of the steps seeing which way she is more likely to get a hug..............
Indy does this on the living room sofa, he likes to leave his back legs on the sofa, front legs in standing position on the floor and head either resting on the coffee table or licking it. I thought this was strange too, glad to see that he's not alone ;D