Use leveled up pigs to tame, much better than moschops! I used 3 tamed pigs, while I rode a stego (hardened plates to prevent being picked up), whistled them around for the desmodus to pick them up. It took a few minutes, but eventually got taking effectiveness to 100%. Then I put pigs away, let desmodus pick me up with blood packs in my 0 bar. Worked like a charm!