The father clearly raised his daughter - Dad is the main thing. You could always find support and encouragement from him. And to suck his cock is just a thank-you for having him. By pulling her on his cock, her father showed how much he trusts her and that secret will be with them now. And the chick did a great job - and daddy is happy and she's even closer to him now.
It makes me jealous, I wish I was in that nigger's shoes with the big dick. Look at the greed with which this chick devours the huge phallus of the negro. At first she's sucking, trying to take in her mouth as much of this mountain of muscles as possible, then greedily devours his dick with her vagina - it won't fit, but she, nevertheless, enduring the pain, keeps pulling herself in as deep as she can.
Staging is super, but the script could have been finished in a more interesting way, for example, either the awakened girlfriend would have thrown the friends out into the street, or even joined them and looking at her friend obliquely would have screwed her boyfriend much cooler than a mulatto!