Masturbation

Masturbating with the hand is forbidden, whether a person fears adultery or not. However, if adultery cannot be prevented except by it, he should give it precedence over it, committing the lesser of the two evils."

Query

Maliki say it is haram even in fear of zina but in necessity, do they say it is permissible or excused or do they say prefer it? What is the meaning of that... In necessity it will be still sin and haraam? Explain the latter statement, what they are saying from However if...two evils.