Used the streets as a conduit
A conduit is a way of transmitting liquids. Jay used the streets to transmit his raps which deal with him being “born in sewage”, and sewage is a liquid. This also ties in with “flow tight” from the previous line because liquid flows.
Jay also pronounces “conduit” like “con do it”, which means Jay used the streets like a criminal, which he discusses in the next few lines.
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