I've answered this at least once before.
Here was the last time (quite some time ago, i might add... damn, i'm gettin' old!)
Anyway, the story is thus:
When i was 17, and a Junior in high school I was dating a wonderful man (wonderful, in this case, is pure sarcasm). As it happened, he was 10 years my senior. OOOooops! (I never got quite around to correcting him when he assumed i was 20). One of my good friends from school, Krystal, found it quite intriguing, and started referring to me as his "boytoy." Well, "BoyToy" stuck, and my immediate circle of friends started to call me BoyToy with regularity (in fact, i'm listed in some of my HS yearbook pictures as "BoyToy").
Some years later i was in college and ran into one of my high school friends. He couldn't quite remember my old nickname and called me "JoyBoy" by mistake. I thought it was hilarious, and the next time i saw Krystal i told her about it. She, too, was smitten with giggles, and smooshed JoyBoy together with BoyToy and thus was birthed "JoyBoyToy."
The 79, contrary to what anyone else may suggest *ignore the avatar!* is simply the year I was born.