Well, as per the 'other thread' we're chatting on if you happen to check up there for baby's head, you might run into your cervix.
Feels like a smooth donut with a dent in the center. You said you where somewhat dialated already (I think) so that dent will be a finger or two wide (or more). Each "finger" is about 2 cm. If you can feel a dent that is about the width of your forefinger (or another finger) you're about 2 cm dilated.
Effacement refers to the "thickness" of the cervix. A long cervix is about an inch thick (2.5 - 3 cm). If it's half that, it's 50% effaced. Also, if it's effacing the cervix will be very very soft like your bottom lip, and it will probably be lower in your vagina. If you have to struggle to find it, (in other words, it's up there pretty far, you're probably still not really effacing.
