Relieving needs is the Clan term for sex. It generally only applies to men and, as in Cro-Magnon cultures, is not associated with reproduction.
Amongst the Clan, having 'needs' seems to be viewed as a biological function for men, with the Clan being unaware that sexual intercourse leads to pregnancy (the Clan believes their totems influence conception). It is not specified if women also have 'needs' with must be relieved; given the patriarchal nature of the Clan, the needs of men seem to be the only ones that are thought about.
Clan men are allowed to relieve their needs with any woman they want, though most would choose to relieve their needs with their mate, and it is considered impolite to have sex with another man's mate without asking his permission. Women of the Clan are taught that they must always be sexually available to Clan men. Clan men have a unique hand signal they give to a woman when they want to relieve their needs with her. Young women, once they come of age, are taught by their mothers the correct position to assume if a man gives them the signal. Some men of the Clan can also relieve themselves via masturbation, but this is considered somewhat shameful and is only done if their are no women present. If there is a woman present, but the man chooses to relieve his needs by himself, it is considered rather insulting to the woman, meaning she is regarded as being very unattractive.
These practices can seem rather coercive, with women being apparently unable to consent to sex. However, Ayla states that most women of the Clan do not seem to mind being chosen to relieve a man's needs. There are even certain gestures and postures women can use to convince a man to relieve his needs with her, suggesting that some sexual encounters in the Clan are consensual and enjoyable for women. This would also imply that the Clan do accept that women can also have sexual desire. Unfortunately, not all sexual encounters in the Clan would be regarded as consensual; however, because men are believed to have the right to relieve their needs with any woman of their choice, the Clan do not have a concept of rape, and most people would consider it odd that woman would refuse or fight back against a man if he chose her, even by women themselves.
This can be especially problematic if women of the Others encounter Clan men - Cro-Magnons are sexually liberal, but sex is always consensual, with rape being viewed as a serious crime. Because Clan men do not understand this, it can lead to them unknowingly assaulting Cro-Magnon women, such as in the case of Brukeval's grandmother. Some Cro-Magnon men are also known to force them on Clan women, due to the fact they don't fight back. This is clearly demonstrated in the case of Oda, a Clan woman who was raped by a man of the Others. She cannot comprehend why the man was so rough with her, saying that if he'd only made the signal, she would've given herself to him willingly, as she was raised to do.
Despite not understanding a concept of rape as Cro-Magnon do, a few Clan men do force women, using violence or intimidation when relieving their needs or deliberately choosing women they despise to cause them harm, such as in the case of Broud, who repeatedly assaults Ayla not because he finds he attractive (quite the opposite) but because he knows she hates him and that forcing her to have sex with him causes her pain and humiliation. That being said, because of their cultural values and beliefs, most Clan people do not view their sexual practices as harmful or violating, though they would be viewed as being so by Cro-Magnon. The use of force or violence during sex is also looked down upon, with members of Brun's clan disapproving of the force Broud uses against Ayla (though they do nothing to intervene on Ayla's behalf).