Bee, this is somewhat perplexing. I've never heard of this, in this location. There is generally no rubbing in this area, so I wonder if there is some sort of seam or something.
For chafing areas, I'm a Vaseline kinda guy, I've found body glide inferior. Bag Balm also good.
Another maneuver might be to take a 2 in wide X 4 in long piece of tape over the area in question.
