Thanks for your question and concern. The chances of being contracted with some venereal disease or any other STD are extremely high after having sexual intercourse that was unprotected even if the penetration lasted for a few minutes. I would advise you to undergo the testing against thevenereal diseases or the different STDs to make sure that you are not caught by any infection on having unprotected sex with your partner no matter for how short time it was. You need to pay attention to the various symptoms such as burning sensation while urinating, fever, and frequent discharge from your penis or the development of spots or the sores on your penis. If you realize any of these symptoms then you should immediately contact your doctor and undergo the STD tests and start the treatment depending upon the results. I would advise you to always use condom while having sex especially when you are going for the sexual intercourse. Using a condom during sex is the safest and the secure method of having sex that protects you from various sexual infections and diseases. You can protect yourself from the venereal disease as well as from many STD that are usually caused due to the unprotected sex. Any change in your behavior too should be examined and taken into consideration by your doctor. I would advise you take your partner as well for the STD test to make sure that your partner too is safe and is not infected by any STD. Always consult your doctor whenever you notice any kind of misbehavior in your body to be on a safer side. Best wishes.