>>2963884
Eh wouldn't really say they're that spherical, it's most just how they look with her clothing covering them. The guy's does draw them having a bit of heft/sag to them but then other times not so much, but I'd say they're more a mix of sphere and heft on average.
Artist:
https://gelbooru.com/index.php?page=post&s=list&tags=feipin_zhanshi