Answer:

plop

Answer	Crossword Clue
PLOP	Penny-in-the-wishing-well sound
PLOP	Alka-Seltzer-in-water sound
PLOP	Raindrop sound

PLOP	Kerplunk
PLOP	Splash
PLOP	Fizz preceder
PLOP	Coin-in-a-fountain sound
PLOP	Fizz lead-in
PLOP	Rainspout sound
PLOP	Soft landing
PLOP	Splashing sound

PLOP	Wet sound
PLOP	Alka-Seltzer sound
PLOP	Fall heavily
PLOP	Fall sound
PLOP	Sit heavily
PLOP	Plunk down
PLOP	Fall with force
PLOP	Onomatopoetic water sound

PLOP	Sit (down) undaintily
PLOP	Sound repeated before "fizz fizz," in ads
PLOP	[frog lands in pond]
PLOP	Alka Seltzer sound
PLOP	Ker finisher
PLOP	Alka-Seltzer-landing-in-water sound
PLOP	Dropping-into-water sound
PLOP	Sit down heavily

PLOP	Alka-Seltzer jingle starter
PLOP	Fall into a chair
PLOP	Sink heavily
PLOP	Leaky faucet sound
PLOP	Sit without ceremony
PLOP	Alka-Seltzer sound?
PLOP	Make a splash
PLOP	Sound of a drop

PLOP	Drip's sound
PLOP	Dripping sound
PLOP	Drop like drops
PLOP	Drop heavily
PLOP	Rain sound