Don't........
Firstly set up your tyres and tubes so they are aligned with the valve this means that you can easily pinpoint the area of interest and check for the cause
Then fit a fresh inner tube.
The punctured one can then be repaired at leisure during a café stop or similar
Do bar in mind though that you will sooner or later encounter the ride where the number of punctures exceeds the number of spare tubes.
Firstly set up your tyres and tubes so they are aligned with the valve this means that you can easily pinpoint the area of interest and check for the cause
Then fit a fresh inner tube.
The punctured one can then be repaired at leisure during a café stop or similar
Do bar in mind though that you will sooner or later encounter the ride where the number of punctures exceeds the number of spare tubes.
I've got a little bradawl which I use at home for the purpose but never thought to take it out on a ride with me.
You have 3 hands....?