According to Jim Recap: Under Pressure
When Cheryl asks Jim to play with the girls while she fixes dinner, he ends up on the pogo stick, which in turns means he hurts himself. Then they go to the doctor, who prescribes some pills for him - but the doctor wants to make sure that the pills don't interfere with the ones that Jim is taking for his high blood pressure. This is a problem because Jim didn't tell Cheryl about his high blood pressure or the pills that he was taking (by grinding them up and putting them in his beer).
Still, she wants to help - so each day she sits him down, brings him a glass of wine to help his heart, and makes him talk. While that doesn't help, the massages that she gives him does, so he starts telling her all sorts of things - even though not all of them are exactly true.
Meanwhile, Dana is in a bit of a pickle because she is going to the wedding of Carrie, who was dating Andy for a while (they broke up in the Pilot episode). It's not that she minds going. She just doesn't know how to tell Andy. So she lets Cheryl tell him. But then it's like one big circle of lies, and it all comes crashing down at the end, and everything ends up right back where it started - life as usual.
