Read the bible. How can you call yourselves clean. Okay just think about this for one minute. Think about how God Created man and woman. Think about the functions of the body parts.
Men have a penis, and women have a vagina.
There functions are for sexual intercourse for reproduction. God made it that way. It is the exit passage of the body's waste. The penis was never meant to enter it. The way it was designed was for things to come out of it, not to go in.