This was heard on a conference call in reference to a price proposal that would be presented to a customer. It is a mash up of “float an offer or idea” (present something informally to see if people are interested) and “dangle a carrot” (encourage someone with an incentive). By the way, carrots do float (I think). This beauty was heard by my chief roving malaphor reporter Mike Kovacs. Of course I thank him profusely.