When you think your partner is mad at you. And you have to fish the waters to find out if they are or if you are just over reacting. you use this phrase to cover your ass.
A semi-Latin word that you can use to make your friends (who hopefully do not know Latin) think you are deep and funny. It's also a great pickup line to use in bars and clubs.
"Yo bitch, my motto is "Carpe Penis"; "Seize the penis"