As a teenager she would 'sneak' out (of her house/apartment) at night to visit her boyfriend.
I'm going to 'sneak' a smoke. [=I'm going to smoke a cigarette while nobody is watching]
She took a 'sneak peek' [=a secret look] at the birthday presents hidden in the closet.
(..) over and over again. Go! Go! - In here? - A detour. Go. he noticed young lovers would sneak into the cornfield. Will you come to bed? Yeah. Soon. Buckley did this, right? Correct. He said that this is our house, this is the police station and that's you. (..)2009 The Lovely Bones