Okay.
So I went to see a friend of mine last night, and we got a little into our cups...
And decided to go play with Poser.
In the middle of trying to put some dress on M4 (don't ask, there was alcohol involved), she says "I can never get the dresses to stay on V4, they fall off, we should try it on M4."
Took me a minute to work out what she was on about, and it was some dynamic dress. Sorry, I don't know who it was by, or what it was called.

Anyway, here is the thing (I watched this...)
She put the dress on V4. Does all the bits to get it clothified and yup, it's there, just fine, covering all the bits.
Applies the pose in the last frame. Adjusts for rotation.
The pose has V4's arms at her sides.
Then she calculates.
As we watch, the dress slowly slides down V4's body, baring her to the navel.
We try with harsher cloth settings. (We were sobering up somewhat, because it was darn annoying) Same thing.
We have the thing almost stiff as a board.
Same thing.
It does not stay on V4's boobs.

So, apart from gluing the thing to the top of her breasts with contrained groups (which make it look weird, because the rest still slides down), what is going on?

I'd call and ask, but the silly girl went on holiday today.
Still, I've had the same thing happening with freebie dynamic stuff, and I really don't know what to do with this.

Anyone able to explain how to stop this?

Silke