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.
(..) What do you need money for? I'm gonna bail Lisa out of Jail. You could leave her there till next Tuesday. Then you could sneak safely away as planned. Yeah, let's see, $ . How much do you need? Well, this is first offense burglary. (..)1954 Rear Window