How do I keep my hair in its style when I lay my head down?

I have an afro and I use gel to slick my hair back, and it works great. But when I lay my head down on a bed or couch to sleep I wake up with my hair messed up like pressed down on my head. So how do I keep my hair style when I lay my head down?

Try sleeping on your side... Or there's always re-applying the gel when you get up.