The drug Zolpidem. Has a sedative (sleep-inducing) effect when taken. Used by Air Force operators to help them calm down after taking stimulants to stay awake during long missions. The opposite of a go-pill.
Also used before a mission to calm nerves and promote sleep.
After flying for 120 hours nonstop, having taken many go-pills in the process, the pilots required a no-go pill to help them sleep.
"Dude, I just got a high-quality fee-vee-dee of that hit movie that's in theaters right now!"
"Don't yell 'Cop!' while around those fee-vee-dee hawkers."
"Alternatively, yell 'Cop!' while around those fee-vee-dee hawkers and see what happens."