how to use COPY within plperl

Hello,
I need to use COPY (instead of INSERT) within plperl function. I know
that COPY will work if data will be taken from file - however I need to
use STDIN. I tried this:
spi_exec_query("COPY sometable (field1, field2) FROM
stdin;"."\n"."sometext"."\t"."sometext"."\n"."\.")

But it didn't work. Thanks in advance.