Old habits die hard (but they do)
All she's trying to is to get him to stop drinking and come out of his room. He's especially cruel now that he's lost Elena again, but Caroline isn't impressed and just goes on with annoying him.
When all other attempts to drive her away have failed, Damon suddenly grabs her, more roughly than he needs to and before she realizes what's happening she's underneath him on his bed.
"If you are so eager for my company, Blondie, you might as well make it worth my while."
The feeling that arises is not unfamiliar, but she's not a helpless girl anymore, something Damon learns when he promptly lands on the floor.
Suddenly he starts laughing. "You really are always good for a surprise, Barbie."