It's a standard TRS jack, not TRRS. TRRS is only used to bypass the mic on IOS devices with our iDevice cable.
With what you're describing, you can run from the output of your TWA to your hardware and back to the TWA via the insert jack with a standard audio cable.
So... the iDevice cable consists of a short TRRS (male) to TRS (Female). And a longer TRS (male) to TRS (male) cable?
Yes, but the signal paths are routed differently for our adapter. Once you've got our adapter, you ca use a longer TRS to TRS cable.