Can I have sex when I have a cold sore?

No. The oral type of herpes (herpes simplex I) usually infects the mouth. However, it can still affect other areas of the body, including the genitals. Herpes infections are extremely contagious, especially when a sore is present. It is important to steer clear of oral sex and kissing until the sore heals completely. It is also important to not use spit while masturbating, as you may infect your own genitals if you are not careful. Use other forms of lube until the sore completely disappears.