There are very little consequences to promiscuity today as long as you're not gay. Heterosexual vaginal sex is very low risk, especially with birth control being widely available. There's a bit of a gender disconnect in risk, but for a male it's even lower risk in terms of catching something than for the female.
Treatment resistant variants of syphillis and gonherea are on the upswing. Herpes is still a persistent problem. And these risks don't care whether you're gay or straight. I don't care what people do (inside the bounds of informed consent), but no matter what, wear a condom and don't share needles.
