Yes you can because it contains very active sperm. The chances are slim but they are still there and if you arent ready for pregnancy the risk isnt worth the few minutes of pleasure.
If you are worried over the chance youmigth get pregnant you can get Emergency Contraception. IT has to be taken within 72 hours of the unprotected sex or sexual contact. Here is a number in which you can use to find a place closet o you that offers it.
Precum is more potent sperm then the ejaculation itself.
I got pregnant off of precum, so if your not into using condoms try something else, like something u insert inside you, they work well when used correctly, that way you dont have to hear the guy complain about using a condom.