Why does my dog suck my tit?

Ok, so im lying on the couch watching japanese porn and as if knowing what to do my dog (a doberman pincher) starts sucking my tit. One day i had peanut butter on my shirt on my breast area and he started licking it, but now its almost everyday and with no stain. It's freaking me out because I'm starting to like it and I just wish i could "do" my dog. Also, my breast are a 32 G, can this be a cause for the sucking, licking and occasional biting that my dog inflicts upon me? I think the reason is because my breasts are really hairy, im talking about Busch Bardens down there, maybe he likes the texture of a hairy boob??? Help me.