How does Lady Macbeth show control in Act 2, Scene 2 of Macbeth?
Lady Macbeth maintains control of the situation (and her husband) in many ways in Act 2, Scene 2.
First, she instructs Macbeth on how to think about the act he has just committed; when he claims, "This is a sorry sight," she replies, "A foolish thought, to say a sorry sight" (2.2.28, 2.2.29). Further, when he expresses his anxiety about his inability to speak the word "Amen" immediately after he'd stabbed Duncan, she tells him to
Consider it not so deeply [....].
These deeds must not be thought
After these ways; so, it will make us mad. (2.2. 41-46)
She wants him to stop obsessing about the murder because she fears that such obsessive thinking will ultimately drive them insane. They need to move on.
Second, Lady Macbeth alone has the foresight and wherewithal to properly frame the chamberlains for Duncan's murder. When Macbeth returns to her, he seems to be in shock and still carries the daggers he used with him. She asks,
Why did you bring these daggers from the place?
They must lie there. Go, carry them and smear
The sleepy grooms with blood. (2.2.62-64)
She knows that the murder weapons must be found with the servants if others are to believe they committed the murder. When Macbeth refuses to go back into the room with Duncan's body, Lady Macbeth places the daggers there herself. When she returns to Macbeth, she chastises him for his cowardice, further showing the control she exercises over her husband:
My hands are of your color, but I shame
To wear a heart so white [....].
How easy it is, then! Your constancy
Hath left you unattended. (2.2.82-88)
While Macbeth laments the act, fears the eternal consequences of what he's done, and seems to cower before a corpse that cannot hurt him, Lady Macbeth manages the situation and her husband with apparent ease. (Though we find out, later, that her conscience begins to eat away at her, too.)
Lady Macbeth first tries to distract Macbeth from his guilt over his murder of the boys, and tells him not to think about it anymore since it is done and over with. Then, since Macbeth is almost incoherent she physically takes the bloody daggers from him to dispose of the murder weapons by planting them on the grooms, in order that they take the blame.
In addition, she gives the distraught Macbeth commands on how they will literally clean the blood off their hands so they do not appear guilty. In essence, she takes charge of the situation, gets rid of the evidence and is prepared appear innocent when the murdered boys are discovered.