"Blood." He doesn't expect the answer will really surprise the other dhampir, but makes an attempt to elaborate. Adrian hasn't asked him to leave and hasn't shied away, both of which would be understandable responses and nothing D would fault him for, and if anyone could understand this...

"Sometimes it can be forced by other means but primarily fresh blood. My own or another's. My abilities increase in response which can be useful."

There's a long pause while he considers if there's more to add or if that is enough, then D continues, each word sounding as though it took some effort to voice: "I was mistaken to try it now."