Good luck with COF, most if not all of the girls I've been with would rather go for CIM than COF, COF gross factor is higher for them. They are scared of the smell of jizz.
But if you want to be persistant anyway, you can always use the olllldddddd trick that might work on naive girls, that jizz is full of protein and nutrition that is a potent and all-natural facial mask. ;)
I have personally never had the cheek to use that phrase, but a couple of my buddies actually claimed to have succeeded.