[ODE] Making floating player bodies properly "ride" moving physicalbodies?

[Megan Fox]

Let me correct myself a bit here - normal friction, I have working just
peachy.  My question is how to calculate the forces applied to the floater
by other moving bodies beneath the floater.

Simple example - a horse-drawn carriage.  Right now, if my player jumps on a
moving horse-drawn carriage, they'll slide right off the back (unless they
happen to get snagged on a piece of the carriage that pulls them forwards).
This is what I want to fix.  Same goes for a large board sliding down a
hill, the player would ideally be able to ride the board, not fall off as if
their feet get no traction on it at all.

-Megan Fox

> I'm sure I can work up a bit of code to properly apply jumping/landing
> forces (land on a pile of boxes and the pile topples - that sort
> of thing),
> but I'm not sure how to go about simulating horizontal friction
> and forces?