That's a interesting and real use case for upper pockets. I can attest doing so the same for both ergonomic and psychological reasons. Plus, there is one reason pockets in lower part of the torso is not very common, it is because the larger leg movements range make the weight in the lower pocket a painful experience in walking and running. The OP design therefore is not very practical IMHO.

Hook your thumbs through your belt loops. Same effect, slightly less slouchy, and more panache.