Methods, systems, and devices for wireless communications are described. A first and second user equipment (UE) may perform a handshake procedure to establish a cooperation agreement designating one or more frequency and time resources which the first UE is to act as the proxy device for the second UE. For example, the first UE may receive a sidelink message directed to a second UE from a third UE. The first UE may determine to act as a proxy device for the second UE with respect to the sidelink message based on the sidelink message being received during a time resource designated for the first UE to act as the proxy device for the second UE. The first UE may proceed to transmit to the third UE feedback information associated with the sidelink message, and may transmit the sidelink message to the second UE on behalf of the third UE.