How do I play an in the staff D (b clef) on a Bb clarinet?

I know that technically a Bb clarinet only drops down to a below the staff E but a piece I'm playing requires one whole step lower to a B clef D (in the staff). Is the only way to play that note to bend it? I can't find any legit that would help and I'm at a loss. I can't get it to bend far enough but I'd really like to avoid taking it up an octave. Any suggestions would help a ton!