🚀 go-pugleaf

How does one tell troff to go to a specific point on the page?  The
man page for psdit in the TranScript package says that

   \!%PB
   \!   postscript
   \!   code
   \!   here
   \!PE
   \!.

inserts the PostScript with the origin of the coordinate system at
"ditroff's idea of the current position on the page,"  which it does.

Great!  So how do I specify "ditroff's idea of the current position
on the page?"  The few things I've tried all produce the same result:
the "current position" is right at the end of the last word typeset.