Boobie TMI

So I was just messing with my boobs, checking for lumps, just holding them (bc it comforts me, I know its werid) and I noticed there was sorta like a bump which I realized a lot more wemon have it than just me so its a normal thing! But I squeezed it and it was like this white stuff came out if it. It looked like whenever you pop a pimple and the white gunk would come out, thats is like almost a dead accurate way of explaining it. Does anyone know what it is? I'm not pregnant and I never have been so it can't be milk, could it?