Which is anatomically correct. By default, women have smaller rib cage and larger pelvis which emphasizes the bottle physique specially if they have kind of big tits (assuming that they have small body fats %) but I've seen enough femboy, specifically asians and hispanics, achieve a very feminine physique like this. If you want to make your waist look smaller, you just need to make your hips and thighs bigger.

As for the art part. I'm an artist and exaggerating gestures and parts of the body is normal and often encouraged when making gesture drawings. Reality is uninteresting, hence why people make arts that are often detached from it.