Being ready to perform a task or duty right away, being there for something;reliable
When the firefight starts, you have to be my Johnny on the Spot with the ammo.
Something, or some person performing an action in precise manner as expected by another party.
Being on time or in the correct place.
Hector, You were hella johnny-on-the-spot with those fries when I got the munchies.
A person who is on hand and ready to perform a service or respond to an emergency; An unusually alert fellow who is capable of decisive action, seizing an opportunity.
When you need help, call me and I will be your Johnny-on-the-spot" "Oooh, thank you, girl!
A portable toilet, or commode.
Man in nursing home: What the hell is that?
Nurse: It's a bedside commode, sir.
Man: I DONT NEED NO DAMN JOHNNY ON THE SPOT!!! I CAN WALK!
The act of shitting on the sunroof of a car, which results in fecal matter splattered on the driver's head/face upon opening the sunroof.
I climbed up on Meredith's car and left her a little johnny on the spot before she left this morning.
A perfectly located restroom; port-a-potty.
Oh, that johnny on the spot really helped. I couldn't have driven another mile!
a massive hickey on the inside of a girls thigh
Steve left a johnny on the spot that was extremely red