My boyfriend keeps developing bumps on his penis within 3-4 days of having sex with me.  The are not herpes blisters, but he says they are painful.  We use water based lubricants during sex  He has no discharge, or other symptoms that would indicate an STD, and his doctor is also at a loss as to what could be causing this.  My vagina is exceptionally tight because I have never had children, and his penis is very large, which is why the lubricants are necessary.  He says that the bumps do not occur every time we have sex, and we are looking for consistent variables that can help us get to the bottom of this issue.