I had sex at 37W and a few days and my water broke the next day:)) not sure if it was the reason, but I heard it brings contractions
My doctor once told me sex, walk and spicy food. You can try that :)
Raspberry leaf teas, spicy food. Being ion your feet a lot. Lots of walking, jumping jacks
you can google pressure points to go into labor and there are usually videos thats what my husband did and it does bring on contractions but mine always stop after an hour or so. Maybe it would work for you since you are dilated already.