Help start contractions

I know this is probably asked a lot but I can't find a thread so I'm asking again! I am 38 weeks 4 days dialated to a 3 and 50% effaced and I've been this way for a month now.. My OB said my cervix is really soft and doesn't expect me to make it to my due date (oct 14) and is just waiting for me to start contracting to get things started. So my question is, other than sex, what're some things I can do to help me contract??