wow, good question!
first of all, for this blog, it’s just stylized as “milkbells” as a matter of choice.
anyway, the story behind the name: when I was in university, I worked at the campus library. this gave me a lot of free time to wander the stacks and read in my downtime. I once found a book of poetry by a Mexican poet. a poem in the book described a woman’s breasts as “two warm bells of milk.” I thought that sounded so poetic, so interestingly put, and it stuck with me for years, maybe because of my (not so) secret lactation kink. when I made this blog, that poem came to mind again. I really wish I could remember the author’s name, or the name of the book. I’ve tried searching, but never found it again.