What is the ruling on touching clothes and the prayer rug with a hand that has the smell of semen on it, and how is the anus to be washed?

Semen is pure, and what your hand has touched does not become impure merely by smelling the odor of semen. Assuming impurity by madhy (pre-seminal fluid) is a waswasa (whisper from Satan), and madhy is purified by washing. Washing the anus is obligatory during ghusl (definition) (ritual bath) from janabah (definition) (state of ritual impurity) by pouring water over it, or by rubbing it with a cloth while pouring water.