You want the -j option. See under "OPTIONS" in the man page:
-jn or --jump-target=n
Specifies a line on the screen where the "target" line is to be
positioned. The target line is the line specified by any command to
search for a pattern, jump to a line number, jump to a file
percentage or jump to a tag.
The screen line may be specified by a
number: the top line on the screen is 1, the next is 2, and so on.
The number may be negative to specify a line relative to the bottom
of the screen: the bottom line on the screen is -1, the second to
the bottom is -2, and so on.
Alternately, the screen line may be
specified as a fraction of the height of the screen, starting with a
decimal point: .5 is in the middle of the screen, .3 is three tenths
down from the first line, and so on. If the line is specified as a
fraction, the actual line number is recalculated if the terminal
window is resized, so that the target line remains at the specified
fraction of the screen height.
If any form of the -j option is
used, repeated forward searches (invoked with "n" or "N") begin at
the line immediately after the target line, and repeated backward
searches begin at the target line, unless changed by -a or -A. For
example, if "-j4" is used, the target line is the fourth line on the
screen, so forward searches begin at the fifth line on the screen.
However nonrepeated searches (invoked with "/" or "?") always begin
at the start or end of the current screen respectively.
Note: you can configure the option using lesskey, use an environment variable like LESS=-j5 man someprogram or just type -j5 while in less.
