Wondadog,
The only way to put on quality mass and not fat is to stay lean. By staying lean you increase your metabolism which requires energy which forces you to be hungry all the time = you grow. All this crap about its good to get fat during the off season and how its ok to be over 12% bodyfat while bulking up is only an excuse for people to justify poor nutrition and to escape any type of discipline during training.
When I started bodybuilding I stayed lean only out of luck because my metabolism was pretty high and I was eating clean. I put on 18kg of lean mass in 1 year.
Also very importantly is nutrition and training style. Hessburger, McDonalds, Lihapirakka, pulla, munkki etc. are in no way shape or form part of a bodybuilders regular diet at any point of the year. Eat right and clean, stay lean, train hard and rest a lot and you will grow guaranteed.