It is impossible to commit suicide by crucifixion. This form of death must be inflicted upon a person by someone else. The Bible speaks of crucifying our old man, that the body of sin might be destroyed. But many Christians try to accomplish this by some form of spiritual self-crucifixion which cannot be done. God is the one who must unite us with Jesus in his crucifixion death and in his resurrection unto life. Do you experience victory over sin through your union with Christ?