Boobs cartoons typically have visually prominent and often unrealistic depictions of breasts. They may be part of a genre aimed at a specific adult audience or used for comical or satirical purposes. But it's important to note that the nature and style can differ significantly from one cartoon to another.
A cartoon woman showing boobs is inappropriate as it can lead to the wrong message being sent, influencing perceptions of gender and body image. Moreover, it could violate censorship and content guidelines in many platforms and media.
I'm not sure. Such a concept is quite strange and doesn't make much sense in a typical birthday context. Maybe it's some kind of unconventional or unique artistic expression, but it's hard to determine its significance without more context.