In one episode of the How I met your mother series, ted is talking about his possible future wife(Robin) Here's the script:

Ted: I just met a perfect woman! She was like this:( He starts to talk about Robin, how they like each other, and how they have a lot in common.)

Marshall: Oh, it is on!

It is on till the break of dawn (with robot motion).

And then there was laughing sound and Ted also laughed.

Lily: But wait. It's only the break of 10:30. What happened?

Scenes back to what happened between Ted and Robin and how they had to leave each other)

I'm not a native speaker, but I think "be on" means something is going to start. Am I right? In this case, what is going to start, and does it have a sexual meaning?

And what does "break" in "break of 10:30" mean? Does it mean "about 10:30," or is Lily just joking about "the break of dawn" that Marshal said?