I've got a question (obviously) from a sentence in a fic that I am beta'ing. I could've sworn that I got someone, somewhere, to answer this question for me once before, but it keeps coming up again and again for me.

"I went back to the bags to pull out a terry-cloth robe and as I did so another bottle tumbled out."

Shouldn't there be a comma before and after "and as I did so," or should there only be a comma surrounding "as I did so"? I think "and" gets included, but I can't remember, and I obviously don't know how to Google search the question correctly.

Thanks for your help!

"...and, as I did so,..."