In Stephen King's "IT", the characters often say "Beep Beep Richie". At first I thought it was whenever Richie talked too much but there were other points in the book when it would be said to other characters and I never quite understood what it meant. Is there something I'm missing or is it just a silly thing they said to stop somebody from going on and on?
I know this is an old one but for posterity...
Like @Bob Stout says, it's a way of telling Richie to stop. Around the internet, there's some talk of it being a reference to the end of a comedians stage routine in the 50s where a horn was sounded but I think it's actually a reference to the Road Runners "Meep Meep" as, when they all meet again as adults, shortly before he tells his IUD story (last part of Chapter 5); this quote appears:-
"Beep-beep, Richie," Ben said solemnly, and then exploded laughter in a hearty baritone utterly unlike his wavering childhood voice. "You're the same old roadrunner"
Perhaps saying that his mouth is running again.