3 risky sex moves to avoid

Doing oral sex with a guy without knowing his history
Cold sores and genital herpes are caused by the same incurable virus. If your man has a sore on his mouth, he can pass the virus to any area where his lips touch your skin. But he can also spread herpes even if he doesn't have a visible sore.

You might think you're protecting yourself because bacterial STDs, such as chlamydia and gonorrhea, live in semen and if your partner doesn't ejaculate, he won't spread these to you if he's infected. Problem is, the bacteria that cause these diseases also thrive in pre-ejaculate. So even if he doesn't reach orgasm, the bacteria can invade your system. Also, since herpes and human papillomavirus (HPV), which can cause genital warts and potentially lead to cervical cancer, are transmitted via skin contact, you can become infected just by his privates touching yours.

The one to worry about here is HPV. If your man has an HPV-related wart on his hand and then touches you below the belt, you could catch this viral STD.