The easiest to break down is probably Russia.

She is posed coyly, regarding the viewer without facing them directly. This may be in part because it’s a reliable head shape to draw, (as we see it repeated in the rest of the figures,) but it’s also definitely within typical body language for flirtation. There is within the piece a general attitude of playful contempt toward the viewer. The composition places the figures to look down at the viewer, India even bends to look at us at our level with a scolding finger, juxtaposed with a smile and heavy-lidded eyes. This is intended to make the figures more desirable, to create in the viewer the feeling of wanting their approval. It’s a common enough sexual dynamic that I hope I don’t have to explain further.

The placement of Russia’s right arm beneath her bust both creates a barrier between the viewer and the figure and, along with her other arm, frames her breasts, which are pushed up. Both the shading (also note the little line between the breasts) and the distortion of the lettering on the shirt serve to highlight the shape. Similarly the shadows on her skirt are applied such that they mirror the pubic region and provide several lines for the eye to follow there. The bite out of this shape even seems to suggest a pubic mound. Around the edges, too we see come into shape the lighter region of the skirt as suggestive of the legs and abdomen beneath it.

You can take a lot of this stuff independently and explain it as something else, but we have to understand that this is being drawn by a person who communicates in this medium either professionally or as a serious hobby. Artists spend a lot of time making these; the composition, poses, etc. are considered and intended for effect. The artist of this piece intended for it to be somewhat erotic and applied a number of techniques in pursuit of that.