Bitcoin client two-way communication When client A opens a connection to client B, it opens its TCP connection to second client's port 8333. Is this connection solely used for A's queries and B's answers to A's query, or can B also query A using the same connection?

For example, A can ask B for list of known peers using this connection, but can B ask A for the same using the connection A established, or does B need to open a new connection to A's port 8333, exchange version messages, and only then send its queries?
Once the connection is established, the communication is completely symmetric-- either end can ask the other anything.