Before you apply oil to your penis, it's best to chat with your doctor first. There's always a risk for side effects and allergic reactions, especially since oils are not regulated. Plus, there's a chance that the oil can interact with medications you may be taking.
For safety, perform a patch test by placing a small amount of the oil on your arm first, checking for signs of irritation or allergic reactions over a 24-hour period. Even if your doctor signs off on your oil and you've done a patch test, the oil can also affect your partner's health — they will need to practice these safety measures before use too.