Deep inside my wife's vagina I find what most certainly must be her "portio vaginalis" or the beginning of her cervix. Several years ago we discovered that she has orgasms if I thrust at the opening with my finger, actually I hold still and she bears down. Lately she has been actually sliding around my finger and I can feel a distinct hard ring moving along my finger some times as far as the first knuckle which would be about 2.5cm. Lately as she slides this opening around my finger, at about 2.5cm there seems to be even firmer tissue which has also beginning giving signs of relaxing. This second barrier baffles me, what is it?