1280. Erin's Boyfriend 06: Matt's Turn

Sameth on Dec. 10, 2014

What Erin is referring to in the last panel is probably exactly what you're thinking it is. In case it's not, I've left it vague enough for it to still be a surprise.
Also, Erin can tell by Matt's reaction more than what he's saying. And he's not much of an actor. He's had some experience, but his expertise is more in directing.