The case study is ASM2. I no longer own my 2 copies of the figure, as I eventually sold them in anticipation of a Civil War Spidey (turned out to be Homecoming -- quite the wait).
Anyway, I didn't get totally crazy with poses, but I didn't hesitate to move him -- there are photos in the ASM2 thread, buried by now no doubt.
Bent legs, outstretched arms, spread legs -- Spidey-stuff. I was more concerned with the seams than the actual material.
Some of the poses would last only hours or days, but one in particular I left for a couple of months.
Upon taking the limbs back to neutral, the suit's blue areas had creases and pouching where it was bunched and stretched out.
After smoothing the suit back into place, I held the figure over a kettle and gave it a light steaming. I was careful with this as even a tea-kettle can produce very hot steam, so I was mindful of not over-heating and melting the plastic-y elements of the blue suit areas.
The suit shaped itself back into place, good-as-new and retained its finish, colour and elasticity.
How many times can you do that? I don't know. At the end of the day these pieces are a trade-off -- obviously not as robust as traditional action figures for all the obvious 1/6 scale reasons.
In videos the blue areas on the Homecoming suit look to be similar if not identical to the fabric used for the ASM2 suit, but only an in-hand inspection will confirm that.
Even then, maybe the fabric is a different blend of materials and will react differently, who knows?
But I do think this is the best 1/6 Spidey to date, and won't hesitate to (carefully) pose him up. Will get 2 copies anyway so I'll have a pristine, museum-ready piece, besides, I want to display one with the Holland head.
I'd go slowly, be mindful of the stretching and careful of seams. I'm really not that worried, but I'm also careful.
Been waiting to use that 
