The Pulled Groin Extrapolation

The Pulled Groin Extrapolation is the third episode of the fifth season of the CBS sitcom The Big Bang Theory. It first aired on September 29, 2011.

Summary
Leonard accompanies Amy to a wedding getting to know her better, while fiancées Howard and Bernadette spend a weekend with Mrs. Wolowitz as a test drive for when they're married. Meanwhile, Sheldon becomes a HO trainiac.

Extended Plot
The episode opens on the group having Thai food. Howard suggests to Bernadette that they should leave for the movie they want to see. However, Raj, thinking that he is invited, gets up to go too, and much to Howard's dismay, he is invited along. Penny has to leave for work as well, following which Sheldon asks if someone can drive him to the new model train shop in Monrovia. Soon enough, everyone has left except for Amy and Leonard, who, despite Leonard's discomfort, stays and reads a book. She asks if she should go, as she has been told that she overstays her welcome sometimes. However, Leonard, although feeling a little awkward, tells her that she can stay as long as she likes.

Meanwhile, Raj, Sheldon, Bernadette and Howard are en route to their destinations. Sheldon is going to the model train store, as they are having a lecture about HO gauge railroading, something of which he heartily disapproves. Howard is incredulous as to how someone as old as Sheldon still plays with toy trains, but Bernadette points out his hypocrisy, as Howard has a closet full of magic tricks.

Howard defends this by referring to them as "illusions", and says that they will be going in the attic once they're married so that she can use the closet for her clothes. Bernadette asks why she would be keeping clothes at his mother's house. Howard says to think of it as their house, but that his mother wouldn't be moving out. Bernadette becomes upset that Howard believes that she will live with him and his mother and tells Raj to take her home, but Howard won't allow it, saying to still go to the movies. Sheldon tries to settle the argument by suggesting to Raj to take him to the train store first, adding that he doesn't care what Raj does afterwards.



Back at the apartment, Leonard has just come out of the shower and Amy is still there, reading his high school yearbook and concluding that he was not at all popular back then. She softens the blow by adding that only her mother signed her yearbook. At that moment, Sheldon comes home from the train store and says that he will never go back there again, due to being convinced to buy an HO gauge model train set. Amy finally leaves, but not before she asks Leonard if he can come with her to a wedding that Friday. Leonard agrees, but asks why won't she take Sheldon. She says it's because the last time he came to a wedding with her, he behaved like a child the whole time there. Sheldon defends this by saying that she promised that there would be scientists his own age.

Later that night, Bernadette goes over to the Wolowitz house and apologizes to Howard about their fight in the car. Howard suggests that she have a trial run with staying at their place. Howard asks his mother if it's OK, which she says is a relief after all the sleepovers with Raj. When she's there at the weekend, Howard asks his mother if he and Bernardette can have some privacy, which Mrs Wolowitz sees as them wanting to have sex. Bernadette gets a little uncomfortable, but Howard assures her it will be fine, until his mother calls out to let her know when they're done so she can have a foot rub.

At the wedding, Amy is having a wonderful time, but Leonard is feeling a little upset, as the wedding reminds him of his "kinda-sorta" Priya. Amy tells him that she has a "kinda-sorta" boyfriend back home who is playing with toy trains, but that she isn't "bitching" about it. She then suggests that they go out on the dance floor, but Leonard says he isn't much of a dancer. Amy says she will lead, and they go and do the Chicken Dance.

Back at the Wolowitzs' house, Bernadette needs to brush her teeth, but Mrs Wolowitz has been in the bathroom with constipation for almost an hour. Howard asks his mother to give up so Bernadette can use it. But Mrs Wolowitz says she can come in, as she won't be embarrassed. Howard says to Bernadette that the problem is solved. All of a sudden, Mrs Wolowitz finally has success, freeing up the bathroom. All this time, however, Bernadette is very disgusted.

After the wedding, Amy is helping Leonard up the apartment stairs, after he pulled his groin while dancing the Hokey Pokey. Leonard thanks Amy for a great time as well as breaking the head off the ice swan so he could put it against his groin. She is very good as spatial reasoning. Leonard then kisses Amy on the cheek as a friendly gesture, which causes her to rush over to Penny's place, fearing that she seduced him. She tells Penny that she will e-mail Leonard in the morning about how he can never have her body, adding that Penny has a better shot with her than he does which doesn't thrill Penny.

After Sheldon tells Leonard that he has a great train night and asks him how his night was, Leonard says he had a great night with Amy, even though his groin hurts as a result. Sheldon then thinks that he had sex with Amy, so he karate-chops Leonard and angrily tells him "She is not for you! Not for you!". Sheldon leaves, with Leonard looking completely confused.



Meanwhile, at the Wolowitzs', Bernadette comes in and says good morning to Howard. She says to him that she and his mother made him a breakfast of pancakes. Howard asks if she is getting along with his mother. Bernadette says it's fine, but their communication is a little tricky as they are different people. However, when Mrs Wolowitz asks Bernadette if Howard liked the pancakes, she screams out in a voice strikingly similar to Mrs Wolowitz's that he hasn't tried them yet. Howard asks if there's butter with his pancakes and Bernadette tells him there is butter-flavored syrup. Mrs. Wolowitz calls out again to see what Howard thinks of the pancakes; Bernadette screams out in Mrs. Wolowitz's voice that he wants butter and so Mrs. Wolowitz calls out that it's butter-flavored syrup, but Bernadette cries out that she just told him that. Howard says that he doesn't need butter, but Bernadette calmly says to him in an American-Jewish accent, "If you want butter, I'll get ya butter." After Bernadette leaves, Howard then complains that he has to cut the pancakes himself, never noticing his mother's traits in Bernadette.

Quotes
Amy: ''Leonard, you may not have noticed, but I am being a delight here. And you're not holding up your end of the evening.''

Leonard:'' I'm sorry. The wedding just reminds me of my kind-of-sort-of girlfriend 9,000 miles away.''

Amy: I have a kind-of sort-of boyfriend who's playing with a model train right now, and you don't hear me bitching about it.

Leonard: [sarcastically]  You sound like you had a great night.

S heldon:'' I did! How was yours?''

Leonard: ''Not bad. I had a lot more fun with Amy than I thought I would.''

Sheldon What exactly do you mean by that?

Leonard: ''Well, turns out she really knows how to help a guy loosen up and have a good time. Although, truth be told, my groin is a little worse for wear.''

[ Sheldon hits Leonard in the shoulder]

Leonard: ''Ow! Why did you do that?''

Sheldon: ''To send you a message. She is not for you!''

Leonard: What?

Sheldon: NOT FOR YOU!

Sheldon Cooper: ''<span style="color:rgb(51,51,51);font-family:Arial,Helvetica,sans-serif;line-height:18px;">All these years, I've been so wrong. The tinier the train, the more concentrated the fun! ''

Penny<span style="color:rgb(51,51,51);font-family:Arial,Helvetica,sans-serif;line-height:18px;">: [about Leonard]<span style="color:rgb(51,51,51);font-family:Arial,Helvetica,sans-serif;line-height:18px;"> ''So handsome! Like James Bond.''

Sheldon Cooper<span style="color:rgb(51,51,51);font-family:Arial,Helvetica,sans-serif;line-height:18px;">: Better than James Bond, because he's tinier.

<span style="color:rgb(51,51,51);font-family:Arial,Helvetica,sans-serif;line-height:18px;">Sheldon Cooper <span style="color:rgb(51,51,51);font-family:Arial,Helvetica,sans-serif;line-height:18px;">:'' It's official! I'm an HO trainiac!''

Trivia

 * Title reference: Sheldon extrapolates (concludes) that Leonard and Amy had sex from Leonard's comment about his pulled groin, how he had more fun with Amy than he thought he would, and how she "knew how to help a guy loosen up and have a good time".
 * Amy didn't go to her prom. Her mother had paid her cousin to go with her, but he spent the money on drugs.
 * Sheldon implies that Penny's mother is fat.
 * Sheldon believes he is the most valued, important member of the group and leader.
 * Apparently, when Howard says Honey, it used to mean Raj.
 * Sheldon creates a guessing game in this episode, where he ask the question: "This four letter word describe either, a printer's type size OR compulsion to eat dirt." Although it is not mentioned, the answer is "pica".
 * Mrs. Wolowitz says that after all of Howard's sleepovers with "the little brown boy", a girl staying over is a big relief.
 * Until his HO gauge starter kit, Sheldon was all for "O gauge or no gauge".
 * Sheldon's interest in trains has also been established in The Bad Fish Paradigm, The Terminator Decoupling, The Irish Pub Formulation, and The Zarnecki Incursion.
 * Howard's mother always cuts his meat for him when it's fatty.
 * Amy draws a mustache on her finger for humor and as an icebreaker for conversations.
 * Like in Season 4's The Engagement Reaction, Bernadette sounds like Mrs. Wolowitz when she screams and once again, Howard doesn't notice, only complaining that there is no butter and that he has to cut the pancakes himself.
 * This episode marks the conclusion of the axion calculation saga on the whiteboards that began in The Skank Reflex Analysis and explored if a dense hot plasma could make the elusive Axion particle. Based on the work of Dr. David Saltzberg, the laboratory plasma generated by imploding a small pellet with an array of 192 lasers at the National Ignition Facility would be incomparable to the solar plasma in the core. The net reaction used (deuterium+ tritium -> helium + neutron + energy) occurs 25 orders of magnitude faster than the proton-proton fusion reactions in the Sun that produce the charged particles thought to radiate axions efficiently. An unhappy face was included on one of the whiteboards, consequently.
 * This episode signaled the first obvious sign regarding Sheldon's possible romantic feelings for Amy. When he asked Leonard how his night at the wedding was and Leonard explained that he never thought that he would have that much fun with Amy and added that she really knew how to help loosen up a guy and that his groin was a little worse for wear, Sheldon judo-chops Leonard and says "She is not for you! Not for you!"

Video
thumb|300px|left|Promo for the episode