What Causes Strong Odor And Cheese On My Penis After Sex?

hi, i have been with my girl friend a few times, and have noticed that my penis and her vagina smell sometimes after sex, and tonight in the bath i was washing and found some white stuff around the head which smelt like really strong cheese, obviously cleaned it away and its ok now, just wondering if you had any thoughts as i had a check up about 3 months ago and i was fine?