christians and oral

Me and my boyfriend for almost a year (next month!!) are both Christian. We are very physically attracted. And we have had oral sex. But we haven't had intercourse. We are both still virgins in that sense. 
We know we want to wait until we get married to have sex (penetration) - and we want to marry each other. And although sometimes sometimes we've said "I wish we were married" we never have a problem stopping if we think it's gone too far. 
My question would be what is your opinion about oral. Do you think it's okay or already crossed the line???