So...Wha? >_< So The - are movements and the | Is the stick 0_o?

Let's try again, shall we? I'm sure there are others who can explain better than me, but here is my version.

This > | < is the actual stick. For example- a ball. Following?

This > - < is the space between where the old onionskin is left, and the ball is next. Still following?

Then, as the easing process continues, the spaces will get larger and larger, then smaller and smaller as it reaches its peak. Get it? If not, I advise you to see some tut's on easing. That might be a bit easier.

The onionskin being the frame infront of it?

Behind, the grey area that's left after you have taken a frame and moved the stick.