Deflector shield

In Sci-Fi, most notably Star Wars, deflector shields are energy fields that could protect starships, battle stations, ground-based structures, and even armies from enemy assault. (Wookieepedia).
The term may also be used as a substitute for the word "condom".

Ben: Hey, Luke! I heard you fucked Melissa last night. Did you have protection?
Luke: U kidding? I switched all power to the front deflector shield.