I saw my ob at 41+1 and I was 4 cm dilated. She did an S&S at about 2:30 and I noticed contractions at about 8:30 that night - DS was born 9:30 the next morning. So for me it worked but the ob said I was very ripe anyway. And it took about a week for me to lose my plug, as you described, just bits every now and then.

Hope it happens very soon for you!!!