Not having coined the phrase myself, I can only
speculate as to the origins of the metaphor.  However,
in the contexts which I have heard this phrase uttered,
it is indicative of the urgency in which the act takes
place, ie. no time to remove the footwear, just get down
to business.
These days, "knockin' boots" can refer to the previously
mentioned activity, with or without the track shoes for
a quick getaway.

Now maybe you could clear up this whole "rock and roll"
thing for me?

- Johnette
Unofficial Non-Geezer Pinhead Rep.
> In a message dated 1/11/2000 5:25:14 AM Eastern Standard Time,
> [log in to unmask] writes:
>
> << Roger that reference, Ralph.
>  You nailed that one! >>
>
> Johnette,
>
> In your capacity as representative of the Non-Geezer Pinheads, would you
> kindly explain to us codgers what "knocking boots" has to do with the
> aforementioned activity, or how this activity acquired the above appellation?
>  We thought, in the olden days, that dying with your boots on was a good
> thing (I think that's what we thought).  Now, apparently you young
> whippersnappers have discovered better things to do with your boots on.  Can
> we be young again?
>
> Now I know what to say, without resorting to technical construction industry
> terminology which might confuse some people, in order to avoid offending the
> bluenoses among us. (Go knock boots with yourself, or go knock your own
> boots) But what do I say to avoid offending the brownnosers among us?
>
> Ralph