Within the speculum of things she did.

Everyone's talking about this passage from Lena Dunham's memoir. I'm just trying to understand it:

Grace was sitting up, babbling and smiling, and I leaned down between her legs and carefully spread open her vagina. She didn’t resist and when I saw what was inside I shrieked. My mother came running. ‘Mama, Mama! Grace has something in there!’ My mother didn’t bother asking why I had opened Grace’s vagina. This was within the spectrum of things I did. She just got on her knees and looked for herself. It quickly became apparent that Grace had stuffed six or seven pebbles in there. My mother removed them patiently while Grace cackled, thrilled that her prank had been a success.

Grace, Lena's sister, was (apparently) 1 year old when this happened, and Lena was 7. I can't picture this scene. Quite aside from whether Lena did something horrible that should be held against her today, the writing sacrifices clarity for some spirit of fun, as if she expected readers to laugh and trip along to the next anecdote. But... what the hell happened? Maybe Lena herself doesn't know, but I have trouble believing that a 1 year old "stuffed six or seven pebbles" into her "vagina." Do I have to buy the book and study the Dunham oeuvre to figure out if she's one of those people who says "vagina" when she means "vulva"?

Vagina or vulva, it's still mystifying. And we're asked to believe that the 1 year old had conceived of a prank and was capable of discerning the success of that prank, that a 1 year old could think about the minds of others and feel thrilled that something she planned had worked out. We're asked to believe that a 1 year old "cackled" and that she cackled while her mother was extracting 6 or 7 pebbles from her vagina. At the beginning of the paragraph, when the baby is "babbling and smiling," she doesn't "resist" as her older sister begins her probe. Are we supposed to think that Grace had a plan to freak out Lena and, having inserted pebbles, she acted like nothing special was happening, in order to make the prank work?

And I can't understand the phrase "I had opened Grace’s vagina." What does it mean to "open" someone's vagina? That sounds like something that would require a speculum. But the writer doesn't seem to anticipate that the reader will stop and think about that. But why not? Who says "I... opened [a baby's] vagina"? I know Dunham has won immense praise for going places other writer's avoid, but how could she be so unaware of how that phrase would hit some readers? At least say "vulva" and give us accuracy (if that's accurate). But why give us a clear picture of a baby's genitalia and speak the language of breaking in? In a cultural climate where we are asked to be very sensitive about what constitutes sexual violation even of adults, why would she present a baby's body like that?

Finally: "This was within the spectrum of things I did." We're invited to imagine other incidents. This one was just a sample — the cutest, funniest anecdote perhaps. But for readers who don't take things like this lightly, who don't laugh and move on to some other anecdote, on some other spectrum, this spectrum is a subject for contemplation. And, since Lena too was a child, the contemplation centers on the mother — the "mother who didn’t bother asking why I had opened Grace’s vagina."