I was watching Pretty Little Liars, season 1 episode 18 (here is this scene on youtube) and there's a phrase I don't understand. Characters recently had an awkward moment, when Hanna had to get in the shower when Caleb was there to avoid being seen by her mother. In the scene I linked they are discussing it and after assuming Hanna "wasn't ready to see that much of him" Caleb says:
"What, and now you think you have to throw down too?"
What does "throw down" means here? I searched for translations of the phrasal verb, but none of them seem to fit. Urban dictionary didn't help as well.
The phrase is important to understanding the rest of their conversation, so I'd really like to know what he was trying to say.