Acknowledged. Based on a sample size of two, it seems to me that google books doesn’t necessarily reveal earliest usages (which are generally spoken, AFAIK). But plausibly, they may show when a term has first “Arrived” as it were, and regardless they reveal a nice plotting of the trend in usage.
Google’s ngrams is a nice tool. (But see below: its reliability is unclear.)
Tough noogies first shows up in 1971. I see that Cecil used it in his 1984 publication.
I’ve only heard the expression from one person, so not a common one where I live and the variation I heard was “tough titty said the kitty, with a smile upon her lips”
Grew up on a farm by a long line of farmers. My mother pointed out phrase to my daughter when cooking/cutting bacon with the rind still on – rind had the “titties” still on them. All pigs have them male and female, females just develop more after having piglets. Think the rest of the phrase was added for the alliteration value.
I’m just guessing but if the original phrase was, “Tough titty said the kitty when the milk ran dry”, then it would be like one kitten looking at the one next to him and basically saying, “I sure am having one tough time trying to suck milk from this teet!” Or the other kitten saying it to the one who’s having the tough time.