The Big Bang Theory Season 6 Episode 12
The Egg Salad Equivalency
Sheldon's assistant, Alex, asks Leonard to attend a lecture with her. When he declines, she asks him out to dinner. He turns her down, though her interest in him gives him a big ego boost. Sheldon gets upset about the situation and asks Amy, Bernadette and Penny for advice about the situation using fake names. His ruse didn't work and they quickly realized he was referring to Alex and Leonard. Penny is upset about Leonard's reaction, but in the end, they talk and make up.
Sheldon wasn't as lucky. He confronted Alex about the situation and talks to her inappropriately. His called into the Human Resources Department when he is accused of sexual harassment. He didn't understand what he did wrong. While in HR, he rats out his friends for their own indiscretions. They are all called into the HR office as well.
Sheldon apologizes to Alex, tells her he must take an online class, and tells her she needs to complete it for him.