Light Fantastic

OMG, I did every Google search I could think of, and got results about muscle building and tendon injuries, lol!! I KNEW there had to be a name for it, thank you!

The pic is of a young, unmuscular actress, to show that these shadowy indentations are not the result of working out, nor is this extended underarm hair. Every contour of the body seems to have a name, so I thought I'd ask.

What I'm using is a small red laser pointer attached to a key ring; I have no technical specifics about it. When I shine it at my finger, I don't see anything except my finger with a red light on it. What I'm hoping to find out is, is there a name for this effect that causes the light to fill the container, and why this only happens with this particular container, not other containers that are also translucent but less opaque?

Light would be reflecting off of multiple surfaces in containers with lower levels of opacity too, though, right, even though they do not show this effect? I'm going to try and attach an image; hopefully you can see that there is an area of bright glow around the dot, and then the entire container is filled up with light at a dimmer level.

If I shine my laser pointer at a container that is translucent but closer to opaque, a red glow appears inside the container, big enough to completely fill the container if it is small. I've tried doing Google searches for an explanation, but I guess I don't know the right search terms to use. Could someone please explain what is happening here, hopefully without mathematical equations? Thanks!