People are giving advice that's well-meaning here, but confusing, because everyone has a different approach to drawing bodies.
There are a lot of different elements to drawing. Breaking the body into shapes is intended to help you block out the overall form, the silhouette and proportions. Trying to give those shapes 3D depth by drawing wireframes onto them or drawing them as 3D primitives like cylinders or spheres is intended to give them volume or mass, like a sense of depth in 3D space. Finally, there's the composition of the image and the sense of momentum and weight, which is what the line of action and drawing these smooth, flowing lines are for.
Each artist has their own way of approaching drawing figures that balance these three elements, and also, people may forget that generally, as you get more confident at just "sensing" the right proportions or what feels like it has depth after years of drawing, you may need to use the blocking in techniques less than you did early on. People often link resources that are a bit too high level a bit too soon and leave a developing artist feeling intimidated by it. They are trying to help, so just try to understand that they're not trying to confuse you.
Here's a trick that works for me on tricky poses: Remember that when drawing digitally, you're allowed as many layers of pencils as you want.
Generally on my first pass of pencils, I draw very loosely, like the gesture and line of action drawings people have linked.
Then I make a new layer and over that, I block in more precise shapes and volumes.
Then over that I can add in the detail and clothing and stuff.
Each layer can be in a different colour, and you can lower the opacity of them as you go, you can flip the layer, you can hide lower layers... Do whatever you need to do, especially on a hard pose like a hug.
When I had to draw this page:
The hug was BY FAR the hardest, most time consuming part to draw. Here are my layers:
First layer: Really rough, just getting in the shapes and motion.
Second layer, drawn over the top, tightens up the shapes and adds detail. If I was less experienced, I might have done an additional layer here for construction of the 3D forms, and if you need to do that with yours, that's not a problem.
Then the Ink layer tightens things up more too:
Use as many layers as you need to use to try to get the composition, the mass and the proportion all looking how you want them. I hope that's helpful!
