RewriteEngine on

# allow only GET, POST, TRACE and HEAD
<Limit PUT DELETE CONNECT OPTIONS PATCH PROPFIND PROPPATCH MKCOL COPY MOVE LOCK UNLOCK>
   Require user terrible_unguessable_nonexisting_username_A1LXchE2oTKO422eRKrf
</Limit>

# disallow TRACE and HEAD
RewriteCond %{THE_REQUEST} ^(TRACE|HEAD)\ .*$
RewriteRule .* - [F]