Davapor, as you said is a herbal drug for preventing premature ejaculation, as it claims. It is a natural drug which contains extracts of graffonia seed, kava kava, folic acid, passiflora extracts etc. These are supposed to increase serotonin levels in the brain by enhancing its production. Serotonin is known to delay ejaculation and it can delay premature ejaculation as well. However, I am not convinced personally or came across studies which prove the effectiveness of davapor. So, I think I am unable to comment about its safety, dosage and efficacy. Take care.