1) If a chick is letting you f*ck her without making you wash yo d*ck first, or at least inspecting it before sticking it in, chances are you're better off not even f*cking
2) That's why women should wax the genital area, not shave
3) That pill in the azz thing is cray, that's a warning sign to you not to f*ck
There is no real rule, because someone can have a disease and not know it, but these are a few of my pointers on when you bow out from a date.
1) Cleanliness is next to godliness. Don't mess with b*tches who are dirty off top (like 70% of white women in college, they dorms be naster than the dudes

), you should try to see a girl's place before you f*ck the first time.
2) Smell test. Don't f*ck anything that smells like the garbage can behind your local butcher
3) Blisters or cold sores, don't risk it, especially with white chicks, 99% of the time they got some form of the herp.
4) If she lets you hit raw the first time, pray my nigz, pray. A girl should at least you if you have a condom. But if she invites you to hit raw, and she's not 40+
I'm sure some of the other playaz got better pointers than me, but that's usually what I look out for. My advise, if you're playin' the field, do it only with condoms, but if you REALLY must play, do it in an out of the way place, like a girl's catholic school or something. Otherwise, stick to building a roster/stable of reliable safe chicks, and put b*tches to the test before you add them to your roster. Don't be afraid to get a b*tch tested before you f*ck.