Magnetic

This might be blood in the semen, which is usally not a worrisome condition unless, possibly, if it continues for a while. It might also simply be one of the normal colors of your semen, as color and texture can change. You can cut back on your masturbation to let things 'heal' and, if it continues and you think it might be blood, then tell your father about it and go see a doctor. Embarassing, I know, but your Dad masturbated, too, and he wants you to be healthy.