@Lushboyx:
I'm sure with HIV it can't infect you when ingested, only if there's sore's or cuts in your mouth.
You are correct. Even if swallowed, HIV is practically impossible to transmit through oral sex alone, even if you swallow. There are two main reasons for this.
1) There is a natural enzyme found in saliva that has a natural ability to neutralize the HIV virus itself. This is part of why there has never been a documented case of HIV transmission from oral sex alone.
2) Once swallowed, the trace amounts of HIV that may be found in the ejaculative fluid are then exposed to things like your stomach acid content, which also has a natural ability to kill the HIV virus itself. Either way, what doesn't get covered by the saliva ultimately gets covered by the stomach acid lining in the end.
This being said though, there are other infections (both STD and non-STD) that you can obtain from oral sex. For example, did you know that especially if the dick you're sucking has foreskin, it can actually pick up things like the strep bacteria that causes strep throat? That's right, this means you can get things like strep throat from sucking an infected dick. I learned this one when I came to find out that apparently, under my foreskin did actually retain some strep throat bacteria from my one ex. This proved to be interesting when I noticed the co-relation between getting my dick sucked and the person who sucked it complaining about strep throat. I would imagine that there are other things that you can contract from this method as well.