Wiktionary
n. (context informal English) A rubber duck (bath toy).
Usage examples of "rubber ducky".
The rubber ducky booth was set up the same way it was at state fairs where contestants got to choose one rubber ducky out of a dozen or so that were swimming by and pick it up to see what he’.
Okay, so you search high and low for the perfect rubber ducky, palm-sized and yellow and so cute he'll carry it around in a small brown paper bag so he can look at it now and then and run his fingers down its rubbery sides and pull down its cute little beak just to watch it flip up again, so cute no one could resist running a tub of water and floating the little guy between his knees and making big waves so the duckster wobbles and bobs up and down like crazy.
When he opened them, he saw Staff Sergeant Koffler looking at him as if someone had stolen his little rubber ducky.