baisse
meaning "drop" or "fall", or also used as baisser, meaning "to lean down or lean over." It does not mean "fuck," as seen in baise, which is also mispelled. Used with "toi," the word creates a command to someone to bend over to later engage in sex that has the connection of a sexual refrence, to which the word "fuck" must have been incorrectly interpreted by others.
Baisse-toi!
(Bend over!)
(Bend over!)