diff --git a/otherbackends/raw.c b/otherbackends/raw.c
index a5b3f427..80ce8fe1 100644
--- a/otherbackends/raw.c
+++ b/otherbackends/raw.c
@@ -46,12 +46,6 @@ static void raw_log(Plug *plug, PlugLogType type, SockAddr *addr, int port,
         raw->socket_connected = true;
         if (raw->ldisc)
             ldisc_check_sendok(raw->ldisc);
-        if (is_tempseat(raw->seat)) {
-            Seat *ts = raw->seat;
-            tempseat_flush(ts);
-            raw->seat = tempseat_get_real(ts);
-            tempseat_free(ts);
-        }
     }
 }
 
diff --git a/otherbackends/rlogin.c b/otherbackends/rlogin.c
index 099f115b..e626eff4 100644
--- a/otherbackends/rlogin.c
+++ b/otherbackends/rlogin.c
@@ -54,12 +54,6 @@ static void rlogin_log(Plug *plug, PlugLogType type, SockAddr *addr, int port,
                        rlogin->conf, rlogin->socket_connected);
     if (type == PLUGLOG_CONNECT_SUCCESS) {
         rlogin->socket_connected = true;
-        if (is_tempseat(rlogin->seat)) {
-            Seat *ts = rlogin->seat;
-            tempseat_flush(ts);
-            rlogin->seat = tempseat_get_real(ts);
-            tempseat_free(ts);
-        }
 
         char *ruser = get_remote_username(rlogin->conf);
         if (ruser) {
diff --git a/otherbackends/supdup.c b/otherbackends/supdup.c
index a46bfd9a..c1867086 100644
--- a/otherbackends/supdup.c
+++ b/otherbackends/supdup.c
@@ -570,12 +570,6 @@ static void supdup_log(Plug *plug, PlugLogType type, SockAddr *addr, int port,
         supdup->socket_connected = true;
         if (supdup->ldisc)
             ldisc_check_sendok(supdup->ldisc);
-        if (is_tempseat(supdup->seat)) {
-            Seat *ts = supdup->seat;
-            tempseat_flush(ts);
-            supdup->seat = tempseat_get_real(ts);
-            tempseat_free(ts);
-        }
     }
 }
 
diff --git a/otherbackends/telnet.c b/otherbackends/telnet.c
index df23f2f2..66f7308e 100644
--- a/otherbackends/telnet.c
+++ b/otherbackends/telnet.c
@@ -632,12 +632,6 @@ static void telnet_log(Plug *plug, PlugLogType type, SockAddr *addr, int port,
         telnet->socket_connected = true;
         if (telnet->ldisc)
             ldisc_check_sendok(telnet->ldisc);
-        if (is_tempseat(telnet->seat)) {
-            Seat *ts = telnet->seat;
-            tempseat_flush(ts);
-            telnet->seat = tempseat_get_real(ts);
-            tempseat_free(ts);
-        }
     }
 }
 
diff --git a/proxy/interactor.c b/proxy/interactor.c
index 8006ae64..ccd3e42e 100644
--- a/proxy/interactor.c
+++ b/proxy/interactor.c
@@ -4,6 +4,43 @@
 
 #include "putty.h"
 
+Seat *interactor_borrow_seat(Interactor *itr)
+{
+    Seat *clientseat = interactor_get_seat(itr);
+    if (!clientseat)
+        return NULL;
+
+    /* If the client has already had its Seat borrowed, then look
+     * through the existing TempSeat to find the underlying one. */
+    if (is_tempseat(clientseat))
+        return tempseat_get_real(clientseat);
+
+    /* Otherwise, make a new TempSeat and give that to the client. */
+    Seat *tempseat = tempseat_new(clientseat);
+    interactor_set_seat(itr, tempseat);
+    return clientseat;
+}
+
+void interactor_return_seat(Interactor *itr)
+{
+    Seat *tempseat = interactor_get_seat(itr);
+    if (!is_tempseat(tempseat))
+        return;                        /* no-op */
+
+    tempseat_flush(tempseat);
+    Seat *realseat = tempseat_get_real(tempseat);
+    interactor_set_seat(itr, realseat);
+    tempseat_free(tempseat);
+
+    /*
+     * We're about to hand this seat back to the parent Interactor to
+     * do its own thing with. It will typically expect to start in the
+     * same state as if the seat had never been borrowed, i.e. in the
+     * starting trust state.
+     */
+    seat_set_trust_status(realseat, true);
+}
+
 InteractionReadySeat interactor_announce(Interactor *itr)
 {
     Seat *seat = interactor_get_seat(itr);
diff --git a/proxy/sshproxy.c b/proxy/sshproxy.c
index 55de65e6..5ab81e61 100644
--- a/proxy/sshproxy.c
+++ b/proxy/sshproxy.c
@@ -44,6 +44,7 @@ typedef struct SshProxy {
     Backend *backend;
     LogPolicy *clientlp;
     Seat *clientseat;
+    Interactor *clientitr;
 
     ProxyStderrBuf psb;
     Plug *plug;
@@ -253,7 +254,7 @@ static void sshproxy_notify_session_started(Seat *seat)
     SshProxy *sp = container_of(seat, SshProxy, seat);
 
     if (sp->clientseat)
-        seat_set_trust_status(sp->clientseat, true);
+        interactor_return_seat(sp->clientitr);
 
     plug_log(sp->plug, PLUGLOG_CONNECT_SUCCESS, sp->addr, sp->port, NULL, 0);
 }
@@ -601,28 +602,21 @@ Socket *sshproxy_new_connection(SockAddr *addr, const char *hostname,
     sfree(realhost);
 
     /*
-     * If we've been given an Interactor by the caller, squirrel away
-     * things it's holding.
+     * If we've been given an Interactor by the caller, set ourselves
+     * up to work with it.
      */
     if (clientitr) {
+        sp->clientitr = clientitr;
+
         sp->clientlp = interactor_logpolicy(clientitr);
-        if (backvt->flags & BACKEND_NOTIFIES_SESSION_START) {
-            /*
-             * We can only keep the client's Seat if our own backend will
-             * tell us when to give it back. (SSH-based backends _should_
-             * do that, but we check the flag here anyway.)
-             *
-             * Also, check if the client already has a TempSeat, and if
-             * so, don't wrap it with another one.
-             */
-            Seat *clientseat = interactor_get_seat(clientitr);
-            if (is_tempseat(clientseat)) {
-                sp->clientseat = tempseat_get_real(clientseat);
-            } else {
-                sp->clientseat = clientseat;
-                interactor_set_seat(clientitr, tempseat_new(sp->clientseat));
-            }
-        }
+
+        /*
+         * We can only borrow the client's Seat if our own backend
+         * will tell us when to give it back. (SSH-based backends
+         * _should_ do that, but we check the flag here anyway.)
+         */
+        if (backvt->flags & BACKEND_NOTIFIES_SESSION_START)
+            sp->clientseat = interactor_borrow_seat(clientitr);
     }
 
     return &sp->sock;
diff --git a/putty.h b/putty.h
index 5c7a01f0..edfd1171 100644
--- a/putty.h
+++ b/putty.h
@@ -706,6 +706,8 @@ static inline Seat *interactor_get_seat(Interactor *itr)
 static inline void interactor_set_seat(Interactor *itr, Seat *seat)
 { itr->vt->set_seat(itr, seat); }
 
+Seat *interactor_borrow_seat(Interactor *itr);
+void interactor_return_seat(Interactor *itr);
 InteractionReadySeat interactor_announce(Interactor *itr);
 
 /* Interactors that are Backends will find this helper function useful
@@ -1468,9 +1470,9 @@ Seat *tempseat_new(Seat *real);
 bool is_tempseat(Seat *seat);
 Seat *tempseat_get_real(Seat *seat);
 
-/* Called by the backend once the proxy connection has finished
- * setting up (or failed), to pass on any buffered stuff to the real
- * seat. */
+/* Called by interactor_return_seat once the proxy connection has
+ * finished setting up (or failed), to pass on any buffered stuff to
+ * the real seat. */
 void tempseat_flush(Seat *ts);
 
 /* Frees a TempSeat, without flushing anything it has buffered. (Call
diff --git a/ssh/ssh.c b/ssh/ssh.c
index 8a70b665..ae7c1f6f 100644
--- a/ssh/ssh.c
+++ b/ssh/ssh.c
@@ -601,15 +601,6 @@ static void ssh_socket_log(Plug *plug, PlugLogType type, SockAddr *addr,
         backend_socket_log(ssh->seat, ssh->logctx, type, addr, port,
                            error_msg, error_code, ssh->conf,
                            ssh->session_started);
-
-    if (type == PLUGLOG_CONNECT_SUCCESS) {
-        if (is_tempseat(ssh->seat)) {
-            Seat *ts = ssh->seat;
-            tempseat_flush(ts);
-            ssh->seat = tempseat_get_real(ts);
-            tempseat_free(ts);
-        }
-    }
 }
 
 static void ssh_closing(Plug *plug, const char *error_msg, int error_code)