I too was scared of induction and went into natural labour at 40 + 4, giving birth early the morning after. Now I don't know if it was coincidental but I had been doing the following things in the days prior to labour -

Lots of walking (or waddling!)
Fit ball bouncing
Massage on the pressure points relating to labour- inner wrist and just near the ankles
Nipple stimulation. I was in fact stimulating my nipples when I felt my first gentle contraction!