do boobs have a scent?

I was in bed with my boyfriend and he put his face in my boobs and just said they smell good, I had just had a shower an hour or two before so it wasn't boob sweat BO and he said it smelt "like me but different". I was just wondering is it normal or even thing? Was my boyfriend imagining it? On Google they said that pregnant women sometimes smell milky but I'm on my period so I don't think it's that.