Can u get a heat rash on ur penis?

Likely something els: You are more likely to get heat-rash and/or jock-itch in the groin, scrotum areas but not likely on the penis itself. So, if you are having the rashes on the shaft, get it checked out as it is possible to have std such as early herpes, warts etc... It is unusual to get heat rash on the shaft and sparing the groin/skin folds areas. Consult doc. Good luck.