Your girlfriend was never private about her kinks.
You'd seen what she proudly reblogged on tumblr dot com, she'd sent you smut and erotic art of all manner of things, proudly flaunting it and even joking about doing it with you.
But by far her biggest kink was forcefem.
Which made it all the stranger that she'd never suggested forcefem or any kind of crossdressing with you.
She knew you found it hot, you had never hidden that, some of your wildest fantasies were forcefem, but it was the only kink she'd never suggested exploring together.
So you pushed her, you intentionally lost a bet to let her choose your Halloween costume, only for her to choose a standard, unremarkable couples costume.
You tried joking about both wearing lingerie for her and about if she thought you'd look cute in one of her dresses and she just smiled and shrugged.
You'd even tried baiting her, making pseudo misogynistic comments about how women dressed or how easy being a girl must be, like in the very same forcefem posts she'd often reblog. But she'd just say something like "I know you don't really think that".
So you caved and just asked her directly, why did she have no interest in exploring that kink with you.
She was perfectly happy to dress you up, eager even, but she refused to give you deniability.
She would not let you lose a bet.
She would not dare you or claim a favour.
She would not let it be a joke or a game, to be forgotten or laughed off.
You would have to beg her.
Beg her to do your makeup,
Beg her to fuck you like a girl.
And only then would she indulge her desires.