An Adult Muslim is required to perform an obligatory full body wash known as (Ghusl) This advice was primarily given to a Muslim prisoner who due to imprisonment was not able to access shower facilities; it can also be applied to any male who due to necessity is unable to access showering/washing facilities.
An adult Muslim is required to perform an obligatory full body wash known as Ghusl after discharging semen as a result of a wet dream or through voluntarily or involuntarily sexual activity or if their penis comes into contact with a females sexual organs (vagina, vulva etc); after ejaculation or contact a Muslim male is considered to be in a state of ritual impurity known as Janabah. When a Muslim is in a state of Janabah they are not able to perform any formal acts of worship in particular the formal five daily Muslim prayers, reading and handling the Quran or completing obligatory fasting and are considered to be in an impure and unclean state. For this reason an observant and practicing Muslim will strive to immediately purify themselves with a full body wash as soon as possible after entering into this state and thereby return to a state of ritual purity (taharah).
The procedure for performing the Ghusl requires every part of the body to be washed and covered with water. This obviously is best done in a shower or wet room and can be done with water in a container or running water; the recommended procedure is stated below.
In constrained circumstances the Ghusl can be performed with a wet cloth/towel/muslin which is rubbed over all parts of the body ensuring that all body parts are wetted (this process also requires a minimal use of water often no more than 1 litre) this can also be done whilst clothed if one is not able to undress (i.e. through wetting the clothing and this then wetting the skin) however this is best recommended when wearing thin clothes.
If a Muslim is unable to perform the Ghusl due to constraints out of their control and power then they should perform it as soon as they are able to do so and there is no sin upon them for this. If they are imprisoned and unable to leave a detention cell then it is advised that ghusl provision be made available to them as soon as it is possible; washing with a wet towel and cloth in a cell with water from the sink would be acceptable just so long as it does not cause major disruption and any adverse health and safety risk. This can be assured by having a towel available when washing half the body at one time then drying it and then washing the other half of the body. Through this method very little disruption would be caused and the obligatory requirement of Ghulsl would be fulfilled and the state of janabah would be removed. Often Muslims in prison need to be instructed by the Prison imam how to perform a ghusl in this way.
Provision of washing facilities in order to enable one to fulfil their faith requirements is therefore a human right and should be afforded to a prisoner; deliberate failure or obstruction to providing this would be regarded as a direct contravention of their human rights in particular the right to observe their faith.
Below I have cut and paste extracts from a mainstream Sunni text on Islamic jurisprudence as it relates to ghusl and related issues. The book is Fiqh Us Sunnah and the author is Sayyid Saabiq and his views concur with the vast majority of Muslims from a Sunni background across the various different Sunni schools of thought.
The online reference is; http://adly.net/fiqh-us-sunnah/www.adly.net/dept/MSA/law/fiqhussunnah/index.html
Fiqh 1.49 a: Discharge of al-Mani owing to stimulation while asleep or awake The opinion of the jurists in general is that ghusl is a must should one have a discharge of al-mani (sperm) owing to stimulation while asleep or awake. Abu Sa’eed reported that he heard the Messenger of Allah, upon whom be peace, say, “Water (washing) is (needed) after (ejaculation of) sperm.” (Related by Muslim.)
Umm Salamah reported that Umm Sulaim said, “O Messenger of Allah, Allah is not ashamed of the truth. Does a woman have to perform ghusl if she has a wet dream?” He said, “Yes, if she sees the liquid.” (Related by al-Bukhari, Muslim and others.)
There are some other points of importance that need to be noted:
“If sperm is ejaculated, perform ghusl.” (Related by Abu Dawud).
Said Mujahid, “We were in a meeting in the mosque with the companions of Ibn ‘Abbas (Tawus, Sa’eed ibn Jubair and ‘Ikrimah). When he stood to pray, a man came in and said, ‘Is there one who can give a legal verdict?’ We said, ‘Ask your question.’ He said, ‘Whenever I urinate, a liquid always follows it.’ We asked, ‘Is it the type of liquid that gives birth to children?’ He said, ‘Yes.’ We said, ‘Then you have to perform ghusl.’ The man went away. Ibn ‘Abbas hurried to finish his prayer, after which he told ‘Ikrimah to bring the man back. He turned to us and said, ‘Is your verdict found in the Book of Allah?’
We said, ‘No.’ He asked, ‘Is it based on the sayings of the Prophet, upon whom be peace?’ We said, ‘No.’ ‘Then from what?’ We said, ‘From our opinion.’ He said, ‘That is why the Messenger of Allah said that one learned man is more difficult for Satan than a thousand worshippers.’ The man came and faced Ibn ‘Abbas, who said to him, ‘When that happens, is it owing to any stimulation?’ He answered, ‘No.’ Ibn ‘Abbas asked, ‘Do you feel any numbness in your body?’ He answered, ‘No.’ Said Ibn ‘Abbas, ‘That is from the cold. Ablution is sufficient.”‘
Fiqh 1.50 a:
If one wakes from sleep and finds some moistness, but does not recall any wet dream, though he is sure it is sperm, what should he do? To be safe, he should perform ghusl. Said Mujahid and Qatadah, “There is no need for ghusl until he is sure that it is sperm, for his prior condition of purity is not ended by an uncertainty.
Fiqh 1.58: Washing all bodily parts
This is based on the following: Says Allah, “If you are sexually impure, cleanse yourselves,” that is, perform ghusl, and “They ask you concerning menstruation. Say: ‘It is an illness, so leave women alone at such times and go not in unto them until they are cleansed,” that is, until they perform ghusl. The proof that cleansing means ghusl is in the verse, “O you who believe, draw not unto the prayer when you are drunk until you know what you utter, nor when you are polluted, save when journeying upon the road, until you have bathed (taghtasilu).” This shows that ghusl, the washing of all bodily parts, is meant.
Fiqh 1.58 a: How ghusl is performed
According to the practice of the Prophet, upon whom be peace, the correct manner of performing ghusl is:
1 wash both hands three times,
2 wash the penis,
3 make a complete ablution (like the one made for prayer–the Prophet used to delay washing his feet until the end of his ghusl if he was using a tub, and so on),
4 rub water through one’s hair three times, letting the water reach down to the roots of the hair,
5 pour water over the entire body, begining with the right side, then the left, washing under the armpits, inside the ears, inside the navel, inside the toes and whatever part of the body can be easily rubbed. This account is based on the following report from ‘Aishah: “When the Prophet, upon whom be peace, took his bath after sexual intercourse, he would begin by washing his hands. Then he would pour water from his right hand to his left and wash his sexual organs, make the ablution for prayer, take some water and put his fingers to the roots of his hair to the extent that he sees that the skin is wet, then pour water over his head three times and then over the rest of his body.” (Related by alBukhari and Muslim.) In one narration it states, “He used to rub his head with his hands until he was certain the water reached his skin, and then he poured water over it three times.” It is also related that she said, “When the Prophet would perform ghusl after having had sexual intercourse, he would call for some water, which he would pour on his right hand to wash the right side of his head and then the left. He would then take water with both hands and pour it over his head.” Said Maimunah, “I put water out for the Messenger of Allah to perform ghusl. He washed his hands two or three times, and then he poured water from his right hand to his left and washed his private parts, wiped his hands on the earth, rinsed his mouth and nose, washed his face and hands, washed his head three times, poured water over his body, and finally moved from his place and washed his feet. I brought him a towel, but he did not take it, for he shook the water off with his hands.” (Related by “the group.”)