Penny and her boyfriend Steven are hanging out on the couch, but they can't take it any further because Penny has invited Sheldon over. Sheldon thinks that he and Penny are going to study together, but Penny intends to just copy Sheldon's assignment. When Sheldon refuses to just show Penny his assignment, Penny distracts him by flashing her tits. Frustrated, Penny pulls out Sheldon's dick and starts sucking. That, finally, gets Sheldon's attention off their assignment.
Lifting her miniskirt, Penny sinks down onto Sheldon's fuck stick and starts riding his dick. Once heh as a taste for that twat, Sheldon is an eager participant. He gets Penny on her knees to take her from behind until she squeals with her climax. When he lets Penny knows he needs to cum, he suggests that he ejaculate on her face. Penny agrees, happily taking a facial. As they put their clothes back together, Penny, who has forgotten to wipe her face, finally gets to see Sheldon's assignment to copy his work.
Eventually Steven comes home and kisses Emma on the cheek before commenting on her funny taste. He goes offscreen to shower, but comes back to hand Penny his letterman's jacket. When the towel falls, Steven decides to make the best of the situation by fucking Penny in front of Sheldon so he can study their technique. Penny is game to deliver another blowjob and then climb into Steven's lap for a second stiffie ride. When she winds up on the arm of the couch with Steven's dick buried between her thighs, Penny lets her boyfriend know that he can't cum on her face. She makes it up to him by jerking him off all over her belly. Moments later, Sheldon lets Steven know that he has gotten to cum on Penny's face, which prompts Steven to punch him.