When Leonard tells Sheldon he needs to use more honey than vinegar on Penny, he tries an experiment where he uses chocolate as positive reinforcement on Penny. Amazing.
Hairy Leonard is very eager to see Penny upon his return from their three month expedition and is a little upset at Sheldon for crashing their good makeup time.
Sheldon: I'll have a diet Coke. Penny: Can you please order a cocktail? I need to practice mixing drinks. Sheldon: Fine... I'll have a virgin Cuba Libre. Penny: That's... rum and Coke without the rum. Sheldon: Yes, and would you make it diet?
