After three handwashings and some time?
Please understand that while it's valid to be concerned about pregnancy, it's important not to be in a panic for no good reason, or treat semen like it's poisonous.
You can find out, before it's a crisis, what activities put you at what risk of pregnancy here: What's The Risk? - Five Easy Pregnancy Risk Assessment Flow Charts.
And what actvisities put you at what risk of STDs and STIs here: A Quickie STD/STI Risk Assessment.
Inform yourself in advance. It's the best way not just to avoid panic, but to make sure you're really ready for where you're going and what you're doing without feeling your way around blindly.
Editor and Founder, Scarleteen
My epitaph should read: "She worked herself into this ground."
-- Kay Bailey Hutchinson