Here's a quick sketch of a blueberry inflation sequence.
I think I've only ever done this kind of thing once, though it was for a commission many years ago. I've never really been into it in the past, though I can't deny that it's kind of turned into a guilty pleasure of mine over the years due to drawings and morphs from certain artists, like Oni-Sai and juicethejock (to name a few).
I still prefer weight gain and other kinds of inflation (such as slime~) over it.