What is this white stuff that comes on the bottom of my penis shaft, its flaky and looks like ringworm, it washes away with water and not sure if it causes itching?

Do you have foreskin? if so may be smegna the milky white discharge under the foreskin . If no foreskin and sexually active may be related to sexually transmitted disease like candida( yeast) urethritis, chlamydia, gonorrhea, . if yeast would also check for diabetes as in men I have seen it as the first sign of diabetes. F/u/w/ MD

It is a normal secretion called smegma. It accumulates under the foreskin of uncircumcised males. Best is to keep area clean wioth soap and water. Other choice- circumcision. Good luck