ok, this is kind of gross, but i'm kind of worried. murphy seems to be having a yellowish mucus type of substance that is on his penis. it's not right after he urinates, but it just appears. it looks like it is coming out of it. it's just a little dot and stays there until he licks it, or it gets wiped off on something. he just recently finished a round of antibiotics for something else. does anyone know any thing about this?