"It's ridiculous of course but I think that's why there is no real word for it. Closest I found was "panther" which is the opposite of a "cougar." (Older woman who likes younger men.)"

I have found an opposite I think is more well known. From Saturday Night Live. Gerbils:
https://www.youtube.com/watch?v=0vsNY40Ym20




• ( https link ) Definition of gerbils
[Anonymouse]