On ‘‘The O.C.,’’ Marissa and Ryan do ‘‘this’’ for the first time.

(Didn’t they first do ‘‘this’’ two seasons ago?)

Plus, Kirsten comes home, and Jimmy sails away again

“The O.C.

The O.C., Benjamin McKenzie

Credit: Benjamin McKenzie: Matt Barnes/FOX

I, along with any other committed viewer with half a brain, got confused.

Hadn’t they been doing it for, like, ever?

Because we’ve done a lot, but not this.”

What have they “done”?

What is “this”?

All that ambiguous wording was hard to work through, but I think we got it.

Everyone clear on this?

They had never had sex.

And now they have.

It’s a huge deal.

And there was even banter!

Wouldn’t that have been hilarious?

Aside from that bright spot, the rest of the episode cast a shadow on almost every other character.

(That’s what they’re going to do, right?

Or am I missing something?

Is the nearest public school in Chino?)

They weren’t, as it turns out.

Kirsten telling Sandy, “I want to live again!”

Good riddance to sleazeball Jimmy.

He keeps entering and then leaving the Newport scene whenever the show wants to spice things up a little.

I liked the way they disfigured himMystic River-style and then just let him go back to his yacht.

Seven of Twelve really needs to ship out, too.

Right now there are hints of this, but nothing that would warrant, say, a two-month detention.

He’s attractive, he’s funny, and he has a hot girlfriend.

Some light teasing I can accept, but harassment of the wedgie caliber?

As Seth pointed out to the dean, “That’s creepy.”

What do you think?

Can Jimmy ever make a comeback?

Will Ryan and Marissa make it in that new school we saw in the previews?

And what could possibly be the cause of the dean’s obsession with the Fab Four kids?