Having anal sex
rather than risking pregnancy
by having sex
the traditional way. This allows for (though isn't advised) unprotected sex without the need to pull out.
However, there have been rare cases where seminal fluid has found its way into the vagina and pregnancy has occurred, so be careful.
"Dude, I totally hooked up with that chick from the club last night, but when we got back to my place I realized I was out of rubbers!"
"Dude, weak! What did you do, Get head instead?"
"Nah, bro, we used nature's condom."