According to Jim Episode 2.09 Thanksgiving Confidential

Cheryl is thrilled when she is offered to be in charge of the set of the girls's Thanksgiving school play. She asks Jim to help her, and he's complaining they don't spend any time together because there's always someone around them. When they finally get alone on the set, they decide to be a little wild and do it behind the Plymouth rock. Unfortunately, Andy and the PTA president walk in on them. They promise to keep it quiet, but Jim and his big mouth brag about it with a divorced father who criticized married life. When Jim and Cheryl's sexual adventures are spread around the PTA board, Cheryl is fired from her set duties, and Jim, feeling guilty about it, stays up all night to finish the job for Cheryl.