It seems like my gf can only orgasm when I give her oral
Is it possible that she can only orgasm with clitoris stimulation and not from sex/fingering?
or is it cause we havent tried hard enough cause oral seems to be the easiest and fastest way so we just end up doing that.
True.
Just do clitoral stimulation during intercourse. There is no rule book that says it has to be one or the other. That is how I usually have to do it. I either stimulate my clit with my fingers or when my hand gets tired... a small vibe.
A lot of women cannot orgasm from just straight sex.
Most need clitoral stimulation which is why most get off on the foreplay rather than the sex.
Try having her do Kegel exercises and squeezing you while you are inside her. It will stimulate the clit at the same time.