Her sister's slut offers sex in exchange for helping her study

This aunt is getting screwed up because she doesn't give a stick to the water and is lost in class, so the last option she has left is to turn to her brother to see if she gives him a hand. He has no intention of helping her in shit, but her sister offers her sex and there things change. The slut is naked, shows her little hair in her pussy, puts all the ass to hallucinate with him and in a moment has him drinking from his hand and with a crazy desire to start fucking her.