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.
(..) A rooftop funeral in Long Beach. How is that for taste? - Who died? - Leo the Fart. Shot yesterday. Somebody tried for Torelli and missed. Leo was tough. Only he could not sneak up on you. If you change your mind, I will be in front of the hotel. - Where are we, anyway? - Home. (..)1993 Last Action Hero