According to the CDC there's never been a case of transmission from just saliva since the concentration of the virus is so low that you'd need liters to be truly at risk - far more than what even the sloppiest BJ would involve.

A lot depends on the condition of the skin, both yours and hers.

There are many threads on this subject on this board if you do some research.

Almost impossible, if not extraordinarily unlikely. We are talking less than one in a million. There has been very few verified cases of HIV transmission from a man receiving unprotected oral sex (and no other contact). The man probably would have to have an open sore on his penis and woman would have to bleeding in her mouth too.

Unless their is a break in the skin to internalized the virus the risk should be zero.  Besides saliva is very harsh environment for the HIV virus to remain intact and viable for long.  It is a different situation if her gum is bleeding which is not that uncommon but the risk is still low.Besides it is relative very difficult (~1/1000) to get HIV even with unprotected vaginal sex with an HIV+ partner.  You should be concern about other more transmittable STDs from BBBJ.