Yep, I was told my the midwife in our ante-natal class to stand on all-fours while watching TV etc or drape yourself over a fit ball. She said the laying back (reclining) position that most people sit in while watching TV keeps the baby in the posterior position. I found standing on all-fours quite uncomfortable after about 10 minutes but she said even leaning forward in your lounge chair (elbows on your knees and your knees lower than your pelvis) will do the same thing.

Good luck!