My gf routinely doesn't orgasm from penetration so I will bring her to orgasm through oral and then move on to penetration. It took a little time for us to figure this out but I'm one of those blunt guys who asks direct questions on subjects that are of interest to me so we were able to get there after a couple of weeks. Consequently, it's is often the gf who initiates sex and oral to orgasm ensures plenty of lubrication (if you're into that sort of thing). Win win I think.