While Lady Lazarus makes a lot of Holocaust references, she also makes a lot of circus (or carnival) references, too. Our speaker feels as if she's always on display for people to gawk at. She's an object that people pay to see. So it makes sense that when she makes her circus metaphors, she's usually suggesting that she has a lack of control over her life.
Lines 25-34: Lady L imagines that a "peanut-crunching crowd" barges in the circus door to see her. They undress her, and she is forced into performing a strip tease. They can see her whole body, and she childishly says, "There are my hands / my knees." As a circus performer, she has no choice but to perform for the onlookers. She becomes a spectacle.
Lines 51-64: Lady L's circus metaphor continues here. She imagines that the crowd wants to consume her—they want to hear her heart, touch her; they want "a bit of blood." And they'll pay a pretty penny for it, too. This imagined circus is a nightmarish one, and we see just how little control Lady L has over her life.