Meaning：
dangerously very uncertain
quick action or movement

Synonyms：
precarious, delicate, dangerous, unsafe

Examples:
a touch-and-go situation
the touch and go of city traffic

Sentences：
The car was in a very bad condition, and it was touch and go whether it would get us home or not.
It was touch and go there for a while during the operation.
a touch-and-go descent down the mountain.
It was touch and go but they finally gave me a seat on the plane

Conversation 1
A: How is your car?
B: Not good, sometimes it starts and sometimes it doesn’t.
A: Didn’t you just drive back from Melbourne?
B: Yeah, it was touch and go all the way, I kept thinking that it was going to stop and never start again, I was so glad when I got home.
A: I’ll bet, why don’t you take it to a garage?
B: I would but I don’t have enough cash at the moment.

Conversation 2
A: How is your father? I heard he was in hospital.
B: Yes, he had a heart attack last week.
A: Is he going to be ok?
B: They don’t know, it is still touch and go, but they should know more when they have done some tests.
A: I hope he is alright, I’ll keep my fingers crossed for you.

(Callan book5, Stage 9 852p)