Maybe this answers the question...
Oral to Penis Contact...
Theoretical Risk: Performing oral sex or "giving a blow job" carries a theoretical risk of transmission for the receptive partner because infected pre-ejaculate ("pre-cum") fluid or semen (cum) can get into the mouth. Any open sores, cold sores, etc. can be a route by which the virus or bacteria can enter the bloodstream and infect. For the insertive partner there is a theoretical risk of infection because infected blood from a partner's bleeding gums or an open sore could come in contact with a scratch, cut, or sore on the penis.
Documented Risk: Although the risk is many times smaller than anal or vaginal sex, HIV has been transmitted to receptive partners through oral sex ("blow jobs"), even in cases when insertive partners didn't ejaculate.
Oral to Vagina Contact ...
Theoretical Risk: Performing oral sex on a woman carries a theoretical risk of HIV transmission for the insertive partner (the person who is licking or sucking the vaginal area) because infected vaginal fluids and blood can get into the mouth. (This includes, but is not limited to, menstrual blood). Likewise, there is a theoretical risk of HIV transmission during oral sex for the receptive partner (the person who is having her vagina licked or sucked) if infected blood from oral sores or bleeding gums comes in contact with vulvar or vaginal cuts or sores.
Documented Risk: The risk of HIV transmission during oral sex is low compared to vaginal and anal sex. However, there have been cases of HIV transmission and STDs resulting from oral-vaginal sex.
( Herpes Simplex is real risk when the herpes sores are evident. )
Hepatitis B is also a risk.
Conclusion:
There is always a risk and everyone has to decide on the risk that they are willing to take.
my 2 cents ... Justin