Referring to the appearance of a woman who has absolutely nothing to offer in the chest. A woman who is Straight up and down like six o clock looks exactly like what the term implies---there are no boobs to break up the straight line appearance when you look at her from top to bottom. Most prominent when viewed from the side.
"Man did you see that chick?"
"Yeah....she is OK but she has no tits..."
"Yeah I know what you mean....she's straight up and down like 6 o clock!"
A painful injury sustained by women during sex resulting from the repeated rubbing of the tops of the feet on the couch as she rides. Oftentimes skin is removed as the injury is sustained, leaving a red patch on the top of the woman's foot, which she will subsequently lie about to cover up the true nature of the injury so as not to be embarassed when she has to go to the doctor or something similar.
" Man my sex feet really hurt from that hot bath I took last night!!!"