When the hairs that surround the anus, still drenched with diarrhea, brush either the nostrils or the bridge of the nose of one's partner during the act of 69ing, thereby leaving a brown streak. Most likely to happen while getting into position for the 69, as there is an enhanced possibility of loss of balance while mounting.

1. The default beliefs installed when you were a child.

2. An unexamined position you absorbed from your environment growing up.