Note: This is a bit of speculation on my part. I suppose this takes place sometime during Kuranosuke's high school years.
One of his ex-girlfriends gave him the idea that started it all.
"I'm so jealous. You're skin is so nice, and you're eyelashes! I'd pay to have those. You'd make a really pretty girl you know."
Kuranosuke only smiles wryly. Silently, he agrees though. It's not mere vanity. It's fact. If he wanted to, he could put (more than) half of the girls who strut around in Ginza to shame.
He's slightly drunk and a lot lonely, when he decides to put on one of his mother's gowns.
Even in his inebriated state, he carefully handles the material, and when he finally slips on the vintage gown he can do nothing but stare at his reflection.
He looks at a mirror and he sees his mother's eyes, his mother's nose, and his mother's lips. It's almost perfect.
His runs his fingers through his hair.
It's the same color and the same texture.
Just the wrong length.
The next day he buys his first wig.
He's horrible at academics, and he hates sports but he finds make up and hair ridiculously simple.
Eyeliner, mascara, foundation, blush, and lipstick. He learns how to put them on and them some. Learning how to style his hair was even easier if that was possible.
His greatest challenge were high heels. Needless to say, he learns a greater respect for women after his first time walking around in stilettos.
It's a lot like playing dress up. It's fun to piss off his father and he thinks it's an absolute riot when men eye him appreciatively.
But the real reason he spends almost two hours everyday perfecting his appearance is to see his mother staring back at him when he looks at the mirror.