1. This is any helmet that has a large cock/dildo attached to the front of it. The helmet should ideally have a chin-strap for extra added control. Depending on the size of the cock this item can really attract some great attention. It's a lot of fun to use too.
2. The head of the penis.
He wore his cock helmet out on Halloween and every dirty-nurse, french-maid, sexy slut out that night couldn't keep themselves from hanging from it.
She did a wonderful job of working my cock helmet as she gave me fellatio.