What have you tried so far?
I can't write your code for you because you still haven't defined the problem well enough.
How does one recognize the response for which the specified token should be sought?
How does one recognize the request to which the specified token should be inserted?
Is the subsequent request generated by the client application, or is the request expected to be generated by Fiddler itself?
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.