1. A reference to genetically repugnant and abhorrent charactierics, noticeable physically and personally.
2. "Furby" is an adjective referring to disgusting attributes (morally poor, obese, lazy, etc.) and "oats" refers to pedigree. Thus, "furby oats" refers to disgusting genetic traits evident in lifestyle, personality, and appearance.
3. Often times the result of inbreeding, "furby oats" are genetic characteristics that put offspring at disadvantages in life in terms of personality, intellect, and appearance.
What God might have said to the Canaanites (unrecorded): "Do not sow your furby oats, for your genes are a pox on humanity! Your inbred hijinx and lifestyle retardations represent the Devil's clutch on humanity! Your gene pool is infested with retardation and a contamination against the world!" And the Canaanites wept... but bred, anyway, sowing their furby oats.
When your partner be thiccc as a Furby.
Damn that's a curvy furby you got there!