Definition: Masturbation [istimna']; the noun form of the verb to masturbate [istamna, to elicit semen], that is, to seek the discharge of semen; in standard usage: making semen come out by other than sex, either unlawfully, such as making it come out using one's own hand in arousal of desire, or lawfully, such as making it come out using the hand of one's wife. This is more specific than ejaculation [imnaa] or discharge [inzaal], as these may occur when one is not awake and without intent, whereas masturbation is necessarily by eliciting semen when the one who masturbates is awake, by whatever means it is done. Men and women can masturbate. It is considered masturbation even if it is done through a barrier [i.e. garment]; Ibn 'Abidin writes: Even if someone masturbates with his hand through a barrier that prevents erotic sensation, he transgresses nonetheless. In Al-Sharwani on Al-tuhfa: If he intends to discharge by embracing a woman, even through a barrier, it is masturbation, and invalidates the fast. Moreover, those of the Shafi'i and Maliki schools declared that masturbation may take place by looking.
Masturbation can be with one's hand, with other kinds of intimate contact, or by looking or fantasizing. Masturbation with the hand, if it is merely to arouse desire, is forbidden by all accounts. … If masturbation with the hand is to quench an excessive, overpowering desire that leads one to fear adultery, then it is permissible by all accounts. …
Masturbation by intimate contact with other than the vagina includes any and all enjoyment of intercourse – besides looking and fantasizing – in other than the vagina, as well as belly rubbing [tabteen], thighing [tafkheedh], touching, or kissing. The consequence that masturbating in these manners has on religious devotion is no different than the consequence regarding masturbating with one's hand, according to the Maliki, Shafi'i, and Hanbali schools; it invalidates the fast according to the Hanafi school, with no atonement. Its consequence on hajj is no different from the consequence of masturbating with one's hand.
Legal scholars are in agreement that masturbation makes full washing [ghusl] obligatory if semen comes out with gushing and delight. … However, if one feels semen coming down his spine [sulb], and grabs his penis, and nothing comes out of it at that moment, and he is not aware of it coming out after this, then he is not obliged to wash, according to all scholars, since the Prophet (SAW) made washing oneself conditional on seeing something. … A woman is obliged to wash if she discharges by masturbating in any way. The meaning of "discharges" is that it flows down to the place where a woman normally washes when she cleanses herself, this being the parts that are visible when she sits down to fulfill her need.
Masturbating with one's hand invalidates the fast according to the Maliki, Shafi'i, and Hanbali schools, and in general the Hanafi school agrees, since penetration without discharge breaks the fast, so discharge from desire even more so. …
Seclusion in the mosque [i'tikaf] is invalidated by masturbation with one's hand according to the Hanafi, Maliki, Hanbali, and Shafi'i schools. …
Hajj is not invalidated by masturbation with one's hand according to the Hanafi, Shafi'i, and Hanbali schools, but atonement [dam, blood] is obliged, since it is similar to intimate contact in other than a vagina as regards its prohibition and enforcement, and is on the same level as regards penalty. However it does invalidate the hajj according to the Maliki school, and they have made a ruling and a sacrificial animal [hadi] obligatory, even if it was done absentmindedly, since the person has caused discharge by doing something unlawful. … Masturbation by looking or fantasizing indeed invalidates the hajj according to the Maliki school, as this is summoning the semen through persistent looking or fantasizing. If someone causes it to come out by a mere look or fantasy, hajj is not invalidated, but he must present a hadi, and this regardless of whether it was done intentionally, unintentionally, or absentmindedly. According to the Hanafi, Shafi'i, and Hanbali schools, hajj is not invalidated by this, and no atonement is required according to the Hanafi and Shafi'i; however according to the Hanbali, atonement is necessary in the case of looking, although fantasizing stands alone in atonement for it.
The majority of legal scholars agree that it is permissible to masturbate using one's wife, as long as there is no objection, since she is where he finds enjoyment; for example if he has a discharge from thighing or belly rubbing. …
Anyone who masturbates unlawfully is to be reprimanded, in accordance with the word of the Most High: { And those who guard their crotches, except from their wives and what their right hands have possessed, for indeed they are not blamed } [Al-Mu'minun 5-6].