QUOTE(N04h @ Oct 11 2016, 23:37)

Hows this
The female knight glanced at her nipples and the tips of the flesh of her breasts that were covered in aphrodisiac, and her beautiful face distorted as she groaned hoarsely.
Well, I interpreted the distorting of the face as the thing that is being looked at, as that's what's right before 見ながら...
But reading again, the を between 部分 and 美貌 makes me question my interpretation, and yours seems to make much more sense.
I'll try one more time.
媚薬をたっぷりと塗られた乳首と乳肉の先端部分・を-美貌を歪めて-見ながら、女騎士は引きつった呻き声を上げた
While looking at her ~breasts bit~, her face in disarray, the female knight ~voice bit~
While looking at her nipples and surrounding breast flesh covered heavily in aphrodisiac, her face in disarray, the female knight moaned spasmodically.