Tough noogies, "an unsympathetic phrase meaning that's your bad luck", dates from the 1970s, according to
Cassell's Dictionary of Slang, and is derived from the head-rubbing meaning of
noogie mentioned by R_M and Threeb. According to the same dictionary,
noogies can also be used for the testicles, but this appears to be unrelated.
However, just to complicate things,
nuggie is a variant form of
noogie (in the head rub sense) and
tough nuggies is also used, but
nuggies can also mean breasts apparently.
Last year, at R_M's request, we accepted
noogie for Chihuahua, along with the variants,
nuggie and
nugie.
Cassell's Dictionary of Slang says that
tough titty,
tough titties, and other variants, date from the 1920s.
Interestingly, there is an Australian slang word
norg, or
nork, meaning breast. You can read my discussion of its origin and usage in the
Ozlip word list, including the theory that the word is derived from the Norco Co-operative, which depicted a cow's udder on its butter packaging.