[Good, because it's their arm now. She's not getting it back. It belongs to them.
(By which I mean, they've gone ahead and started to lean on it in earnest, almost like it's a little pillow.)]

What do you mean by "coloring"? I have not heard the word "color" used as a verb, before...
Nor have I ever held someone in my lap, either. It sounds a bit strange - would you be comfortable sitting upon me?
I am not very soft.

[Of course, they're more worried about her comfort than their own. What if they're bony and weird and uncomfortable??? Surely that's worth worrying about.]