More than likely you can shrink the bed/sheet that you linked to earlier, as it (one item) is an object with just sheet "morph".  The sheet is not dynamic, it's pre-shaped with settings to set different "pre-loaded shape" settings.  You can't just shape it however you want, it's pre-shaped in limited numberous ways only.  Since you're new in 3D, that's obviously not an easy explanation.  You'll just have to get it and look at it to know what I'm talking about.

Dynamic things, however, forms the shape around whatever you let it fall on, just like a normal sheet.  This bed/sheep prop (we call it static type when referring to non-dynamic) has only certain limited amount of pre-shapes.

What I meant by "froze"... again since you're new, that too might be a hard thing to explain.  To "freeze" a dynamic cloth, you "halt" it from being dynamic anymore, and it won't go in any different shapes again.  In Daz Studio, you export it as an object (such as like the bed/sheet you're talking about except without any pre-shaped options) so you can use it later, but it won't be dynamic in any way.  When I "froze" the dynamic cloth, I was able to re-size it in a different scene when I imported it back to Daz Studio (after exporting it).  But dynamic cloths or clothes while they're alive (not froze), they can be shrinked, but the'll expand back out when you drape (action) it.

I hope I explaned this.  This is the best way I can explain, you'll have to actually experience these type of things to really know what I'm talking about.

...wolfie