I'd love to be able to do this but I can't keep my centre of gravity over my feet if I put my feet flat on the floor (no matter how widely I spread my knees), so I just end up toppling over backwards. If I do it with my back against a wall, my knees start to hurt after about 30 seconds. I just don't think my body is designed to squat like that. Or do the lotus position, for that matter.