diff --git a/test/fuzzing/README b/test/fuzzing/README
index 4bac9b82..77e5fd80 100644
--- a/test/fuzzing/README
+++ b/test/fuzzing/README
@@ -27,18 +27,22 @@
 
 - If there is another patch to apply, then add a fuzzing tag so that the
   packets can easily be differentiated and appended to the official
-  "fuzzing_spa_packets" file:
+  "fuzzing_spa_packets" file.  Note that adding the --fuzzing-class argument
+  assumes that a patch has been applied to lib/fko_encode.c to manipulate SPA
+  packet data after the various user-supplied data has been provided (and this
+  data itself is valid - it is the encoding itself that the patch is supposed
+  to mess with).  If the --fuzzing-class arg is left off, then the user fields
+  are built using invalid data.
 
-    # ./test-fwknop.pl --enable-perl-module-pkt-gen --fuzzing-pkts-append --fuzzing-test-tag "no_colon_1"
+    # ./test-fwknop.pl --enable-perl-module-pkt-gen  --fuzzing-test-tag "encoded_non_digit_rand_val"  --fuzzing-class encoding
 
       [+] Starting the fwknop test suite...
 
-          args: --enable-perl-module-pkt-gen --fuzzing-pkts-append --fuzzing-test-tag no_colon_1
+          args: --enable-perl-module-pkt-gen --fuzzing-test-tag encoded_non_digit_rand_val --fuzzing-class encoding
 
-              Saved results from previous run to: output.last/
+          Saved results from previous run to: output.last/
 
-       [perl FKO module] [compile/install] to: ./FKO.......................pass (1)
-       [perl FKO module] [FUZZING] generate invalid SPA pkts...............pass (2)
-
-       [+] Wrote 169 fuzzing SPA packets to fuzzing/fuzzing_spa_packets.tmp...
+      [perl FKO module] [compile/install] to: ./FKO.......................pass (1)
+      [perl FKO module] [FUZZING] generate invalid encoded pkts...........pass (2)
 
+      [+] Wrote 30 fuzzing SPA packets to fuzzing/fuzzing_spa_packets.tmp...