Manual Tranny Oil temp preparation

Hi Guys,
i have a question to you Stick shift racers. How do you manage to get a good temperature in your tranny oil?
I mean, i´m in Germany and weather here is not as warm as in the us.
Sometimes we sleep at the track and when you wake up in the morning, its about what...6°C.
To get temp in the motor is clear, just let it run. But in the tranny is nothing really moving. And then i get pretty hard shifting.
Any idea how to heat up the tranny oil? Or have a idea for better Oil? I use 85W90 right now.