"Loin" is never not creepy

Every once in awhile, I feel a combination of delight and annoyance that "cool" rhymes with "school." At some point in our language's evolution, "cool" stopped being merely a word meaning "sort of cold" and became a word also meaning "popular with the youngsters," and I'm sure when that point arrived, some well-meaning educators rubbed their hands together and said, "Finally, we can form a phrase to convince our young charges to continue their educations (thereby ensuring continued employment for us)!"

I read somewhere that 40% of the average person's waking hours are spent thinking in parenthetical asides. But anyway ...

"It's cool to stay in school." I'm curious about the first time that sentence was used, and I'm also curious if the person who used that sentence that first time was as totally un-cool as I think they must have been. I googled "it's cool to stay in school" (all in quotes, obviously, because I'm interested in only the real thing) and got a surprisingly low 745 hits. After the first page of results I was as uninterested in continuing this line of inquiry as you are in reading about it now, so here are some choice snippets from those first ten results:

It's Cool To Stay In School, Diddy Tells High School Students ...
www.starpulse.com/news/index.php

brad's life - It's cool to eat at school.
I remember those, and also "It's cool to..." stay in school, follow the rules, and other such idiotic rhyming phrases that belittled the intelligence of the ...
brad.livejournal.com/2155583.html

Toys & Hobbies at ShopSheet.com
It's never too early to learn that it's cool to stay in school and hip to be smart. This small desk is packed with big style. The seat features a pullout ...
www.shopsheet.com

myLot - hushuoyoudao - my discussions
i miss school a lot...here are the ten reasons it's cool to stay in school: 1. School is where you met your bestfriend--the one you can't live without. 2. ...
www.mylot.com/hushuoyoudao/discussions?t=reply

Uh-oh, I feel a lame transition coming up ...

Here we go ...

I still don't know when it started be cool to stay in school, but if the characters on Mad Men came up with it, I'd have a new appreciation for the phrase. Mad Men is a delightful new drama on AMC about a Madison Avenue advertising agency in 1960, and by "delightful," I mean "delightful if you can look past the misogyny, anti-semitism, racism, homophobia, and sense of class entitlement." Hey, some people can't.

I can. I love it.

There's background to the scene below, but I think it works fine without.

Fig. 1: I think "cherry danish" is supposed to mean something