The commandment was a property crime, not a purity crime.  Nocturnal emissions, (the closest thing mentioned in relation to masturbation) required taking a bath.  Sounds about right.  

Was Jesus obedient to the lawful authority of the pharisees and the scribes?  He was said to be without sin, not immune to it because of his divinity (that would have been really cheap grace).  You need to rethink the concept of obedience. You conflate it with loyalty, not truth.

Conscience comes from many sources, including reason.  It includes the right to call foul when the Church claims a monopoly on reason, especially when in doing so it avoids evidence.

Remember who is writing the checks.