Going to try and write a Novel in 30 days starting in November!

Write a novel in 30 days?
What the fuck am i going to write my novel about?

I was put up to this challenge from a Co-worker, he said i should write what i know about sex! But how am i supposed to write this? How am i supposed to come up with this?
Should i go towards like a 50 Shades of Grey type novel or like a Twilight?
So confused! So lost!

HELP!!!!

Cant wait to do this! I'm not really a writer but what the hell!
I can try! Can't I?!
We will see!