I had a friend whose wife used to service the drivers from the German embassy - and when she was done for the evening, he'd be given the privilege of eating her pussy. For the longest time, I couldn't get my mind around how that could possibly be appealing...and it's difficult to see my own behaviour from anything other than my own vantage point. But somehow I got to thinking about it the other day....and I thought "How's that really much different from what I've been up to over the years?" Really, it isn't.
I think it depends on what your fantasies are - and how horny you are at the time. I can come when sucking someone off (from the adrenalin rush?). However, I think in his case it was also a fantasy of subjugation, which perhaps she enjoyed as well.