Ive noticed you've answer a lot of vague questions here, so I thought I'd ask my own. I occasionally get what look like pimples on the under side of my penis. I have had blood tests and never tested positive for anything. My girlfriend of 1.5 years has never had anything like pimples on her genitals. We both get canker sores inside our mouths during times of serious stress, and got them both we were dating each other. Recently she got a small bump on her vulva, that looks like a pimple. Is it possible that we could have transmitted the virus that causes the canker sores, to genitals through oral sex?

First of all, it is not completely clear as to what causes canker sores (apthous ulcers), if they are viral in nature, and if they can be transmitted to another person. See my response to Ulcer on the uvula for more information on canker sores. I have not been able to locate any information that suggests that canker sores can be transmitted to the genital region.

It's hard to tell what you have on the underside of your penis. The shaft of the penis can have many small bumps that are completely natural, many of them occuring at the hair follicle. If they've always been there, that's probably what they are. However, any changes that you notice which are unusual or cause you concern should be checked out by a doctor.

RMK