How to stop poofy hair!?

Okay. i am a 13 year old boy with Justin Beiber like hair. I really like the way his hair looks, but i have one problem. Whenever i get out of the shower or when my hair gets wet, when it dries it looks poofed out in the back/sides. The only way i can fix it is by using gell and just putting a lot of gell in the back(up and a little behind my ears) or wearing a hat. Wearing a hat is all i can do, it flattens out the back/sides, which is what i want, but i get really bad hat hair. I shouldnt have to wear a hat to get my hair the way i want. When its fully dry it looks kinda sqaure and poofy in the back and on the sides, thats all i can say. Please help me someone!