Many of the militants are spending part of their monthly salary on little blue pills and on kinky underwear for their so-called wives, in order to be able to maintain their sexual prowess.
The report has revealed the details of the 'twisted sexual appetites' of the militants and oppressive treatment of women based on the injuries the women sustain while being ravaged by the fighters.
The fighters take numerous 'wives' to satisfy their demand for sex, from among the 'sabaya' – kidnapped women and children, some of them as young as nine, who have been sold into sex slavery.
The fighters also try to force women into marriage, which is greatly supported by their commanders.
The report says the new practice is at odds with local rural customs; traditionally young men and women would marry their cousins or other relatives in order retain their family bonds.
The militants are said to pay a dowry of between £2,000 (around $3,000) and £5,000 ($7,700) for each marriage, depending on whether a woman is from the city or the surrounding countryside.
The increasing poverty in the region makes the deals work and forces the families to sell their daughters to jihadi husbands.
The whole atmosphere leaves the girls and women utterly miserable and in some cases suicidal.
The male relatives of the forced brides are also being offered jobs both within the terror group and the local area, "in order to win the [somewhat] reluctant support of the local citizens."
The activists say that "ISIL barbaric treatment of the local female population has seen women risking their lives by trying desperately to escape their marriages. If they are later discovered, as many of them are, the women are stoned to death either as apostates or adulterers."
As part of their brutal treatment of women, the Islamic State fighters demand that all the females completely cover their bodies in public – including their hands; insist that women only venture outdoors when accompanied by a close relative, and prevent any woman older than 50 from leaving the house, except during medical emergencies.