Posing is a very important part of planning a photography work in portrait photography. Speaking about photographing a mother, maybe there are some exceptions or variations on this theme, because we can give a complete different meaning to the picture, just with some little composition variations.
In iTunes or in all the digital libraries you could find very big manuals about posing, and only about posing. That’s because there is a complete “science” about how to pose correctly in pictures, also according to the kind of work you’re going to do, or the goal of the photoshoot.
If you want something more natural, like a everyday lifestyle photoshoot, is not so necessary to think about posing. In this case, you only need to be a little bit annoying: try to shoot pictures when she is not expecting it. In this eventuality, you will surely have some unique shot, in which the situation captured by your lens and film will be a moment that no one will be able to recreate in the future.
The other opportunity is to have some ideas about posing before starting the shoot. What I usually appreciate is not adopting very complex poses, because it’s usually enough to be really simple, without starting with millimetric positions. If you start being too annoying about the perfection of poses, your model (in this case your mother) will surely look unnatural and really not relaxed in the final results. This is not what you want to obtain, right?
My suggestion is to not respect the standard female posing techniques for your mother, because the traditional rules of female posing are made in order to give a specific goal: they are meant to underline explicitly or implicitly the sexual meaning of women’s curves and body. I personally think that having a photoshoot with your mother should have a completely different goal, like (for example) produce a humble and sweet portrait.