Related Clues:
- Leak indicator, maybe
- Lottery holder, once: Abbr.
- Pressure cooker sound
- Org. that registers 18-to-25-year-old males
- Air leak sound
- Sound from a frying pan
- Sign of an escape, perhaps
- Evidence of a leak
- Viper's warning
- Unwelcome boarding-pass marking
- Sound of a soda can opening
- Adder's warning
- Deflation indication
- Threatened snake's sound
- Org. protested by 10-Down