Get on birth control or have some condoms handy (and use them). It is so easy to get caught
up in the moment and end
up going all the way. Then, you will have a change of getting pregnant.
But, again, it is a perpetuation of a myth that one sperm can cause pregnancy. It cannot happen. This comes from a day and age, when it was thought that it only took on lucky sperm to meet up with the egg to get pregnant. This, in the past few years, has been proven incorrect.