The lady is just a great body and very flexible, and she's an ace in the anal! Clearly visible is the coverage of the cock entering the anus, the man clearly takes great pleasure. To extend the pleasure longer, he alternates between anal and sucking, so you can last much longer. But not all ladies agree to it, the majority take in the mouth after anal only if anal took place in a condom.
I think after such a pressure of males, the lady would be just happy to have one-on-one sex! Rarely have I met a lady who would really like it when a bunch of men fuck her like a last back alley bitch!