If it's jock itch, it's caused by a fungus and should be treated with anti-fungal cream made for the purpose. As the skin heals it may be dry and flaky from scratching, and using a moisturizer made for the penis like Man1 Man Oil could be helpful.
Your girlfriend has a penis
Okay so I work in the heat all day long at least 9 hours a day and I workout a lot and I just started getting this rash type thing on my penis like the side not the head or anything it's kinda itchy but not all the time only when I stop moving I just bought new boxers and I sweat a lot also I masterbate like everyday and shower and have sex never everyday just maybe 3 times a week what could this be