Something like this?

my @mesages = (...);

my $pass = 0;
for my $message (@messages) {
    sleep(5) if !$pass++;
    print($message);
}
[download]

sleep is interruptible and drift can occur if the loop body is non-trivial, so maybe the following would be better:

use Time::HiRes qw( time sleep );  # Optional

sub sleep_until {
    my ($e_time) = @_;
    for (;;) {
        my $dur = $e_time - time;
        last if $dur <= 0;
        sleep($dur);
    }
}

my @mesages = (...);

my $s_time = time;
for my $i (@messages) {
    sleep_until($s_time + 5*$i);
    print($message);
}
[download]