Johnny-on-the-spot

Johnny-on-the-spot  {adj. phr.}
At the right place when needed; present and ready to help; very prompt; on time.
A good waterboy is always Johnny-on-the-spot.
The firemen were Johnny-on-the-spot and put out the fire in the house soon after it started.
Compare: ON THE JOB.
Categories: time {adj. phr.}