More commonly known as Fuck Me Boots. Comes from abbreviating Fuck Me to FM, which is also an abbreviation of the radio broadcasting band of Frequency Modulation. Normally used when talking around persons who may or will be offended by the term Fuck Me Boots.
Dave: "Did you see that chick that walked in with the radio boots? Any higher & she wouldn't have needed that belt she's wearing as mini-skirt."
Greg: "I know, can't half tell why she's here..."