An idea perpetuated on manosphere
blogs that women casually sleep around in their 20's with hot, non-commital player types.
Then, supposedly, when they hit their 30's and lose their looks, they realize they wasted their prime man-snagging years and become desperate to settle down, often with a boring, dependable flavor of guy they previously had no interest in.
Karen spent her late-twenties riding the cock carousel with a bunch of guys in bands that just wanted sex. Now she's 33, past her prime, and dating an accountant who's she's pressuring to have kids with.