A fuck towel is a slut which serves much the same purpose as a towel one would ejaculate into. She does this by letting guys use her instead of, or in addition to, a towel in order to ejaculate without making a mess.
"Man I gotta bust a nut its been a long time."
"Just use the fuck towel dude, she's in the other room."
n. a promiscuous female, especially one who has sexual congress with superiors in order to secure advancement in her career.
Kevin Spacey: Dawn here, she used to be quite the little fuck-towel. Film school grad who fucked her way to top assistant. Fucked her way to junior executive and then fucked her way to VP. It was quite a rise.