A: Pourquoi ne pas ... en attendant ?
B: Pas besoin de me le dire deux fois ! J’ai hâte de ...
I assume this is an enthusiastic way to express your agreement with a suggestion, but I wonder if it is the equivalent of "Now you’re talking" or "You can say that again".
If so, it is interesting to note that in English you ask for the statement to be repeated, while in French saying it once suffices.