Last night, the girls and I made an impromptu trip to the bookstore to buy my friend Laurie Notaro’s new book, “The Idiot Girl and the Flaming Tantrum of Death: Reflections on Revenge, Germaphobia, and Laser Hair Removal” (info at www.laurienotaro.com).

The book had been released just that day, and I had to grab it (and three copies to give to friends) because despite (or maybe because of) her pottymouth and more-than-ascerbic tone, the secret about this NYT bestselling author is that she’s got the softest heart between here and Eugene, Oregon, where she sadly escaped a couple years ago.

I tried to explain the whole “my friend Laurie wrote this book” thing to Annabelle, who seemed a little confused and didn’t remember the time the three of us had lunch at the now-defunct soul food restaurant next to my office. (Laurie’s a big fan of chicken fried steak. Annabelle had the mac and cheese.)

My favorite story about having Sophie and telling friends is that when I told Laurie about Sophie, she took all but one mention (a really vital one, it would have ruined the essay to remove it) of the word “retard” out of her forthcoming book (not the one I bought last night, she’s written so many I’ve lost track). I love that she did it, and even more, I love that she left it in once. I would never want a good piece of writing ruined!

I wish Laurie had been with us last night.

At dinner before the bookstore, Annabelle insisted on sitting next to Sophie, across the table from me, to take care of her sister. It was practically luxurious, even when I had to reach across the table to grab Sophes — who insisted on standing up in the booth to dance.

I also had a moment of private humiliation when I started obsessively eyeing a little boy with Down syndrome, only to realize that he was, instead, part Asian. (At least, according to the membership of his booth, he was.) That I kept to myself (til this overshare — who’s the Idiot Girl???) so it didn’t upset our little dinner party.

But back to the best part: Annabelle caring for Sophie. It’s always bittersweet, as I fastforward 20 years and freak out about AB being burdened with a sister who can’t live on her own (although as Ray said recently, who knows about that) but if I stay in the moment, I beam.

The sister-love continued at the bookstore, gelato shop and even in the bathtub, when things usually melt down. For the first time ever, Sophie agreed happily to have her hair shampooed and rinsed — perhaps because there was a new stylist in the tub:  Annabelle.