How to fast for one who is unable to marry

Question:
The Prophet (peace and blessings be upon him) said: “O young men, to the end of the hadith. Is the fasting required to be consecutive, or intermittent?

Answer:
The Messenger (peace and blessings be upon him) said: meaning, if he is able to afford the expenses of marriage, let him marry, for it is more effective in lowering the gaze and more protective of chastity. He encouraged marriage, and urged fathers to hasten in marrying off their sons and daughters, and not to reject a suitable suitor when he proposes. They should cooperate in facilitating the mahr (bridal gift) and the wedding feasts, and not be extravagant in these matters, so that they make it easy for their sons and daughters to fulfill what Allah has prescribed regarding marriage.
As for one who is unable and cannot afford it, he should fast, as the Prophet (peace and blessings be upon him) said, and practice chastity, for Allah has commanded this.
Fasting can be consecutive, and it can also be intermittent; there is no harm in either, depending on his condition and ability. If he fasts consecutively, that is good, so that he may restrain the evil of desire. If he fasts intermittently, there is no harm. The matter is up to him, for he knows his own condition best. Fasting is recommended and prescribed in order to mitigate the harm of desire. If he takes some medications that alleviate this, that is also good.
Among the greatest remedies is lowering the gaze, and staying away from wandering in the markets without need, and looking at women in the markets, or in his home if he has non-mahram (relatives one may not marry) in it. He should be cautious in such cases and refrain from letting his gaze wander, for this is among the greatest causes of his safety. As for letting the gaze wander and roaming in the markets without need among women, this is among the greatest causes of fitnah (trial, discord or temptation), the release of desire, and the occurrence of immorality. We ask Allah for safety.