When having doggy-styled sex, you replace your penis with a beer bottle (or perform anything totally unexpected and/or vile), thus prompting her to give you an incredulous look from one side of her face.
Since her back is facing you, she couldn't spin her head completely around to give you that look (unless she's Megan from The Exorcist), thus resorting to face you with one side of her face, looking like a fish laid flat on one side.
When used in the context of man on man action, it can be re-worded to One Eye Lance Bass. A dedication to the out-of-closet NSync member.
While doing it doggy style with my girlfriend, I ejaculated into her without prior consent. She gives me the one eyed bass, and proceeds to kick me in the nuts.