both #1 and #2 for me were "stuck" behind my pubic bone during labor, and with encouragement to walk and rock my hips we were able to get them both to turn and deliver vaginally. DS had been in such an odd position for such a long time that he had a big lump on his head (called a subdermal hematoma) that calcified and is still on his head now 3 years later. i've always said that i would've ended up with a c/s both times had i not been with wonderful, skilled m/w's.
neither were posterior, but were occiput transverse (meaning head-down, facing sideways). so this last pregnancy i spent most of my energy and focus in the last trimester on getting baby to present properly - seeing a chiropractor once a week, doing the spinning babies inversions, being careful not to do a lot of leaning back in chairs and on the couch, etc. and it worked - she was completely posterior at 37 weeks, but was perfectly anterior by 38 weeks and stayed that way until birth and was the only one of my babies born with a nice round head