Two words of the U.S. Army phonetic alphabet that create the acronym F.P., which stands for 'Fuck Pig', indicating a female soldier of lascivious bent who is not shy about taking on lovers. 'Foxtrot Papa' came into usage during the days after the Women's Army Corps (W.A.C.) was terminated and women (formlery known as WACs) were mainstreamed into the regular Army. 'Foxtrot Papa' was used in order to politely convey intimate information about female soldiers while avoiding sexual harassment charges. (Miliary usage circa 1970s and '80s)
Related term: Puss-in-Boots
I hear Spec-4 Betty is a regular Foxtrot Papa.