I learned meditation (and a lot about Sufism) from an older book by Puran Bair (One of Hazrat Inayat Khan's pupils) Living from the Heart. Anyway, he has a blog he started with his last book and it's an excellent source of advice for meditation. He has answered similar questions about evoking kundalini naively a few times:
www.energizeyourheart.com/blog/archives/87
www.energizeyourheart.com/blog/archives/86
www.energizeyourheart.com/blog/archives/70
www.energizeyourheart.com/blog/archives/16
If you've done Heart Rhythm meditation before, use the water breath and start with about 8 Heart Beats in and 8 out. It's basically downward meditation focused on your heart.