you may have noticed femcelpaw and more recently, unnamed ratcel, wearing a shirt like this. it's an in-universe anime that's kind of a cult classic. she's called puni puni princess because her boobs get really big in her Kira Kira (or 'Sparkle') mode. it's totally not pornographic, it's extremely empowering for women everywhere.
surprisingly PPP is making a comeback. there's a remake in the works, but the original creator isn't involved, so it's probably gonna suck.
also you (yes you) will be able to buy this on a shirt sometime soon.