When I try to have one (still learning) and get extremely close to the PONR I can hold it back when I hit it and keep masturbating for a while or some times I come. But when I don't come, I'll keep masturbating and some sperm will ooze out since I guesse I had a dry orgasam? But I wouldn't wanna risk getting her pregnet! Yes she's on BC...
If you're looking for safety against infection or the need to avoid pregnancy (assuming she's not on birth control!) THERE IS NO SAFE SEX WITHOUT CONDOM - ORGASM OR NOT! Sorry for shouting, but really I'm just stating the bleeding obvious.