"tock" is short for BUTT-tocks.
"tick-tock" is also onomatapoeic, describing the sound made by shoes or high heels.
George W. Bush: "tick-tock, twelve-o-clock." (the girl walking right in front of us has a fantastic ass i can't stop looking at. are you looking at it too?)
Dick Cheney: "tick TOCK." (yes, i see. it is quite remarkable)
George W. Bush: "tick-tock you don't stop" (i could look at that ass forever)
Dick Cheney: "you know what time it is." (i agree wholeheartedly)
George W. Bush: "tick...tock...tick...tock"
Dick Cheney: "hmmmm... tick-tock, three o'clock." (look to your right)
George W. Bush: "tick TOCK."
"Dude, I know, we just gave away our money to the Fat Man."
"I was so drunk at the Tick-Tock, I don't remember making out with him at all!"
While eating young Marsha’s pie
She stuck in her thumb, and tick-tocked Miss Plumb
And said, Ooooohhhhhhhh, spank me hard, you dirty bi*ch, make me squirt, harder, ooooohhh that’s it, don’t stop, AAAAAAARRRGGGHHHHHH.