jump = copulate with?

[Laurence Horn]

>I do not find "jump (vt) = copulate with" in OED2.  When does it date
>from?  Chapman, 1995 (the only slang dictionary I have at home), says
>"by 1638", but (as typical) without any direct and datable citation.
>
>Joel

then there "jump X's bones".

This reminds me--I just heard a line in a song referencing ashes and
the hauling thereof.  Does anyone have a more or less reliable story
on how we get from "have/get one's ashes hauled" to the sexual
reference, or vice versa?  I googled my way to some suggestions and
assertions, but none seemed especially convincing.  (I confess I
don't have my HDAS on me; maybe the answer lurks therein.)

larry