I know how you can bring on labor, but what about postpone?

I just found out I'm pregnant (4 weeks, 2 days), and I'm due on Thanksgiving (November 24)!! I'm pretty excited about that. I've been researching ways on how to bring on labor (as my family tends to carry 2 weeks late), but I thought it'd be really nice to have a baby in December. So, I'd have to carry at least 1 week late to get into the "December" area. As long as the babies healthy, that's all I care about. And I know when the baby's ready, it's ready! Just thought I'd ask if you know and tidbits on how to postpone labor - just for fun!