Wear a hat

Common parlance in England for wearing a condom

Man 1: Oy! That one's a knock out.

Man 2: Don't matter how pretty she is mate. Always wear a hat.

Wear it as a hat

When a male pulls his scrotum up and over the head of his penis prior to becoming erect and displays the act to his sexual partner and shouts, “wear it as a hat”! The male then proceeds to become erect and have coitus.

Wear it as a hat- What are you doing with your penis? *proceeds to pull scrotum over head of penis* Wearing it as a hat of course!”