Seegee:
That's really cute, Phil, but it suggests to me that young Kate will find herself turned over the royal knee on a regular basis.
Ahhhh well, to me "babykins" doesn't suggest the right kind of kink for this Library.
If Prince William were to playfully call Kate "young lady" or "little girl," IMHO that would be more suggestive of a spankophile relationship--as would "mistress" or "madame" in the other direction, of course... --C.K.