An effective jab towards a man when he is behaving in an obviously less than masculine manner. This term is far more insulting than "douchebag".
*Disclaimer: Someone really needs to earn this title. No willy-nilly usage, please.
Teddy: "Did you see that shirtless, Italian guy cruising in his convertible Mitsubishi Spyder while blasting Rihanna? What a cunt swab, right?"