deca dick is erectile dysfunction. it has nothing to do with libido, prolactin, and somewhat estrogen.. keep in mind deca aromatizes way less than testosterone or dbol does, so blaming deca dick on estrogen makes no sense scientifically or practically. in the old guys guys loved deca because of this, they didn't have access to AI's like we do today. they always ran proviron with it, they didn't know why but they just knew it worked.
well i can tell you the reason it worked was because nandrolones increase DHN in the body, swamping DHT. it would be like running finasteride, major dick killer.
so you should use a DHT derivative with a nandrolone for this reason.