First of all, whether circumcised or not, you need to keep your penis always clean. Wash properly when taking bath. If your penis is not circumcised, pull the skin back gently and clean the head of the penis. If you don’t do this, smegma (dead skin cells) can build-up leading to smell and infections.
In regards to Sexually Transmitted Infections, a circumcised penis is less prone to contract easily. However, practicing safe and healthy sex is always important.