like raven said you have to reign supreme over the other males of your tribe
the first thing you should do is, if you're not already, circumcise yourself and burn the excess skin as a offering to our true gods, the backyardigans
secondly after then you should piss all over her, mark her with your scent, and if necessary burn your initials into her skin with a rusty spoon you had on a stove for an hour
after this you'll want to piss on everything else in a three mile radius, any objects, any landscapes, any buildings, any people, especially women, because only then will the other men understand your burning tribe leading power
finally you need to establish your primal essence to the world
just have fun with her, and don't start getting dozens of other women pregnant. not like i'd know what its like to have a girlfriend though