I agree with those posters that say that "deca dick" does not exist. There is a "steroid withdrawal/post-cycle dick" and we've all experienced it...
ANY steroid will surpress your natural testosteron production, deca not more or less than others. Totally normal. You can do a post cycle with HGC or clomid. Or you can stay on a certain maintenance dose of test. after a cycle is over. Or you can just suck it up and wait until your natural testosterone production has kicked in again.