I keep a condom in my wallet, just in case!
Y'know... it's not just the guy's duty to make sure that the sex doesn't result in a pregnancy. It takes two to tango, make sure that you bring your dancing shoes ;)
Or more correctly said, I used to. I've lost it. Can you believe it? I asked my boyfriend to buy them just in case(I'm 16 and still a virgin), and he gave me one so we would both have one. But now, I can't seem to find it anywhere, and am dead scared my parents will find it XD