lol, I can stack Paris on the table so she's standing well, and then generally I aim the camera, half-press the shutter button to focus, and then toss something over where I want her to look, and take the pic when she looks over to it! I praise her for looking over at what I threw, so she's always happy to watch whatever I toss over (a toy, a bit of fur, a comb.... haha, whatever is handy!) but I have never tried to teach her to keep her head still, away from me, in a stack for a pic.
This is a good result of tossing something:
You really need to teach her to look at something specific in the direction you want her head to be, NOT to teach her to try and teach her to keep her head still (she's watching you cos that's what poodles DO! They watch and follow their owners!) You need to teach dogs what to DO, not what NOT to do; they cannot grasp the 'do not do' thing very well at all, so trying to teach her to 'do not move your head' works a whole lot better if you can teach her 'look at this spot until I say otherwise' which you can certainly do with clicker training just like you'd train a target (google it if you don't know about target training) but IMO tossing something works fine for me, cos I can't be bothered teaching her to look at one spot! haha.
In saying all that, I still get better stack photos outside with her in a free stack, cos she's good at staying, even in a stand, if I tell her to, so she'll stay in a nice stack but is generally happily sniffing the air etc so I can usually get a good full side on pic outside a lot easier than on the table inside.