I came across this picture while looking at a tumblr collection that had plenty of interesting stuff in it. This one stood out because it seemed to cry out for an explanation of how the scene came about.
It is interesting that each of the four blow jobs looks to have a different character to it. The guy on the far right is basically using his woman's mouth to masturbate into. He is holding his shaft in one hand and her head in the other moving her backwards and forwards at a pace that he finds pleasing and satisfying - probably waiting for just the moment he is most aroused to come into her mouth which will be just where he wants it to be.
On the far right the story is similar, but he is just guiding her efforts letting her do more of the work. Next to him the woman with the long blond hair is having to do all of the work. The man is younger, less experienced and less used to using a woman to give him what he desires. He seems more interested in what is happening to his left.
And well he might. This woman has completely taken the initiative and is holding the man's cock skilfully and is probably using her expertise to give him a most satisfying and arousing suck. Her very enthusiasm is evident by the way she is holding her body more erect than the others suggesting she is taking her duties more seriously than her sisters.
How did the scene arise? I imagine these are four guests invited around for dinner to discuss business. Big business. The kind of business where making sure they go away satisfied is paramount. The master of the house is no doubt watching the whole scene carefully to make sure his hospitality is appreciated. I imagine that the performance of the women will be monitored. Any of them that fails to delight their customer will no doubt end up feeling the whip later on when the guests have left, darkness has fallen and nobody can hear the screams.