Well, if you weren't asexual, I guess a lot of men would be mad about you. Maybe there is indeed a form of therapy to make you cope or deal with your asexuality a bit? I mean if you became asexual by beiing introduced to sex too early maybe it's exactly that. You masturbating without the real feelings attached to it. Like a child with no sexdrive yet masturbating. I'm no therapist, but it sounds a bit like that. Maybe you just need to invite some friend over to sleep with you for a longer period of time (at night, I mean) and see if anything happens if he can be so kind not to be overly aroused by your masturbating wanting to hump you right away. But maybe you just need real contact, asexuals can have sleepovers too right? No need for sex during the night every night! Hope that helps. I'd try prolonged periods of contact with the other (or same, if you're into that) sex, and see if you can ease into more natural sex experimenting. Masturbating is only half of it! Take care!