Burning sensation on vagina right after sex?

You could be allergic. But, if he has a large penis, or you don't have sex often, he is being rough, any of these thing could cause it. As long as it goes away after a few hours, it is probably nothinng to worry about. ALso, incase you didn't know, you are supposed to urinate after every time you have sex. It will help prevent infection such as a UTI.