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.
(..) - Damn kids! - Really. - Yeah. - (KIDS GIGGLING) KID: Oh, my gosh. CAMILLA: Keith and I are going to sneak out tonight with his friend, Michael, who wants to meet you, by the way. No way. If my mum ever found out, I'd be dead. So don't get caught, you priss. (..)2016 The Conjuring 2