well..., he uses his hand to point out to you and show the numer he wants it to be: "three"; that is an invitation to take part in a threesome. In the second sequence you can see only the two other guys fucking, but "you" are there. At least I was when I edited the vid, behind him, licking his asshole clean; that was my role and the way I percibed it....
This is the video description: "Black wants a threesome with you and another one" So how would you know he wants a threesome if you actually don't know him?