Deny all methods excepting POST and GET

RewriteCond %{REQUEST_METHOD} ^(TRACE|TRACK|OPTIONS|HEAD)
RewriteRule .* - [F]

Rewrite all aliases for a domain to a single domain

RewriteEngine On
RewriteCond %{HTTP_HOST} ^(www\.)?mydomain1\.com [NC,OR]
RewriteCond %{HTTP_HOST} ^(www\.)?mydomain2\.com [NC,OR]
RewriteCond %{HTTP_HOST} ^(www\.)?mydomain3\.com [NC,OR]
RewriteRule (.*) http://mydomain.com/$1 [R=301,L]