As an STD assistant, I understand this is a sensitive topic, and I want you to feel comfortable asking these types of questions. Regarding your specific query, there are a few STDs that could potentially be transmitted through contact with semen, even during activities like hand jobs.

Herpes simplex virus (HSV) and human papillomavirus (HPV) are two STDs that can be passed via skin-to-skin contact or contact with bodily fluids like semen. If there are open cuts or sores on the hands, HIV and hepatitis B could also potentially be transmitted through blood exposure, though the risk is generally low from this type of activity.

It's important to note that proper hand washing and avoiding contact with semen can help reduce transmission risks. However, the only way to fully prevent STDs is through abstinence or being in a long-term, mutually monogamous relationship with a partner who has been tested and is STD-free.

I would advise speaking to a healthcare professional for personalized guidance based on your situation and sexual history. They can provide counseling, testing recommendations, and help weigh your STD risks. Please don't hesitate to reach out for support - your health and well-being are the priorities.