The Big Bang Theory
Sheldon (Jim Parsons) and Amy (Mayim Bialik) spend the night together in episode 11 of "The Big Bang Theory" Season 9. CBS

Sheldon (Jim Parsons) made "Shamy" shippers swoon in episode 10 of "The Big Bang Theory" Season 9 when he crashed Amy's date with Dave (guest star Stephen Merchant) to profess his love and give Amy a great, big kiss. Now the show's brainiest couple is back together and are looking to take their relationship to the next level. For Amy, that means finally spending the night together. How did it all go down in the winter finale, "The Opening Night Excitation"?

When the episode begins, Sheldon, Leonard (Johnny Galecki), Raj (Kunal Nayyar) and Howard (Simon Helberg) are racing to buy tickets to the opening night screening of the new "Star Wars" movie. However, Sheldon has a problem. They bought the tickets before he got back together with Amy and the premiere is the same night as her birthday. Uh oh! Luckily, he gets some guidance from Emmy-winner Bob Newhart, who returns to the show as Professor Proton, this time dressed as Sheldon’s personal Obi-Wan Kenobi in a dream to help the scientist make the difficult choice. Proton convinces Sheldon to spend the night with Amy.

Now Sheldon has another problem -- what to get Amy as a gift. He runs two options by Penny (Kaley Cuoco) and Bernadette (Melissa Rauch). The first is a far-fetched chance to play harp with an orchestra, the second is the least romantic sounding, sheep and wool-themed getaway ever, the last option is ... sex! Yes, Sheldon suggests getting intimate with Amy to show how important she is to him. Although the thought makes Penny a bit uncomfortable, she tells Sheldon to go ahead with the plan.

"Then it's settled, my gift to Amy will be my genitals," Sheldon declares.

Meanwhile, Leonard, Raj, and Howard head to "Star Wars," bragging that they will have much more fun than Sheldon, who bailed on them. Bernadette, knowing Sheldon and Amy's hot and heavy plans, says that is not true.

"Knowing them ... they will," Penny counters.

However, the trio does hit a bit of a snag when Will Wheaton (guest starring as himself) shows up to the theater -- the group gave him Sheldon's ticket -- in a "Star Trek" costume. Now Leonard, Raj, and Howard must endure jeers from other "Star Wars" fans. On top of that, Will reminds the boys that the movie could disappoint them, a thought they do not want to entertain!

Meanwhile, Amy has her apartment all decked out for a romantic evening with candles, flowers, and dim lighting. Anyone can see how Amy would like this night to end ... anyone except Sheldon, of course. When Amy asks to skip dinner and get right to the presents -- "Give it to me," she asks -- Sheldon asks her why. Sheldon just can not take a hint!

Watch Amy try to seduce Sheldon in a scene from episode 11 below:

Eventually, they make it to the bedroom. Amy is nervous. She does not know what to expect and says she has built this moment up in her head for a long time. Ironically, Leonard, Raj, and Howard are having the same thoughts about "Star Wars."

"We will figure it out together," Sheldon promises. They kiss ... and then they get hot and heavy. It goes well and Amy is particularly pleased! Plus, Leonard, Raj, and Howard love the movie! "The Big Bang Theory" ends the winter finale on a high note.

"The Big Bang Theory" will return with new episodes on Jan. 7.