diff --git a/beetsplug/lastgenre/__init__.py b/beetsplug/lastgenre/__init__.py
index 3df7a15d06..16d27030a6 100644
--- a/beetsplug/lastgenre/__init__.py
+++ b/beetsplug/lastgenre/__init__.py
@@ -431,14 +431,14 @@ def commands(self):
             "--keep-existing",
             dest="keep_existing",
             action="store_true",
-            help="keep already present genres",
+            help="combine existing genres with new ones",
         )
         lastgenre_cmd.parser.add_option(
             "-K",
-            "--keep-none",
+            "--no-keep-existing",
             dest="keep_existing",
             action="store_false",
-            help="don't keep already present genres",
+            help="don't combine existing genres with new ones",
         )
         lastgenre_cmd.parser.add_option(
             "-s",
@@ -452,7 +452,7 @@ def commands(self):
             "--items",
             action="store_false",
             dest="album",
-            help="match items instead of albums",
+            help="match items instead of albums (default)",
         )
         lastgenre_cmd.parser.add_option(
             "-a",