Yes, taking care not to catch anything is important, particularly if you have other sex partners in your life.
But no one here has mentioned the issue of catching one and then telling the SP from whence you think it came, about it. Such a pronouncement, even if made in good faith, usually terminates the relationship immediately with the SP and invokes a response, that almost always goes along the line, "I was just tested and I am fine. It is your problem". Now, you know what you did with her, and you know if you have something, that either she gave it to you, or you got it from an earlier date, and likely gave it to her. So chances are in you mind that she has it and is spreading it. Only once was there ever a gal who sent me back a copy of her report, confirming that now she was ok. No other information though, like did she take pills and get cured before the report?
So with this subject you are damned if you do and damned if you don't. If you don't tell her there is a pretty good chance that she will spread it afar before she is detected. And a lot of damage can be done. So my gut reaction if I had something, notifiy eveyone involved. It is not appreciated, I must tell you. People do not like being told they are or might be infected. You get treated like you are "dirty" when in fact, it had to come from someone you deal with and might have gone to others.
But some of these diseases go pretty well unnoted. Like Chlymidia, can go for months in your body, symphtoms either unnoted or not enough of an issue to do something about. Yet is being spread easily, and in fact there is a rash of it in the lower mainland right now. Spread sexually and orally too.
Body fluids spread diseases, particulary sexual fluids, and many of these disease can reside in the mouth or throat, and be spread back. So avoiding body fluids is the best practice, in any form. BBBJ will force saliva down your urethral track with can be bring bacteria with it. They do not flush out with cum.
IF you are going to exchange fluids with a gal and she tells you she has never caught anything, beware. Those are always the nones who have something. They are the ones who have not got a disease that is bothering them, and the the testing is not always thorough. One gal who told me she was tested regularly told me she had not told her doctor that she was in the trade, so he was not ordering all the tests. Her excuse, well, he is my family doctor since I was small and did not want him to know about this.
So buddy what will you do if you catch one?