Do this all the time. Some examples are.
Spoken to my GF while balls deep in my FB, GF thought I was doing work (I kind of was) and as I was fucking her I was on the phone looking into my FB eyes saying things like "Yes its proving really hard but I can do it. I thought it was a one man job but now I am doing it I think it will be a two man job"
As luck had it I had arranged for a mate to join in for a threesome so left them to it while I finished talking to GF.
FB also called her husband so he could listen.
Met a few couples and single guys and they have been willing to call people while fucking or being sucked by my FB.
They have called, wives, gf's, work, bosses, family, friends one chap even called a customer service
My favorite was a guy who cum inside her while on phone to his pregnant wife, everyone had to stay really quite. He made some excuse about sneezing lol