I have a girlfriend, Amy, that has been studying the last few years and had several casual jobs to bring some extra cash in.  Earlier this year she started doing what she promised was only front desk receptionist work at night for an escort agency / brothel. She was there to greet customers and handle bookings.  I started dropping her off to make sure she was safe but became comfortable with it after a month or so.

One day she came home and said the owner, Danny, asked if she wanted to do a "try-out" to start getting a few bookings.  I asked what a try-out was, to which she replied that Danny gives the girl a personal session to see if they are up to working standard.
"But you're not interested to do that right?" I asked.

Amy pulled a $100 bill out her purse. "I knew we were short on rent this month, so I thought it would be harmless and I didn't think it would be penetration anyway"
Now I was taken back "hang on, so there was penetration or not?" I queried, my mind racing back to when she was giving me a blow job just that morning and seemed incredibly horny.

She offered up details, as if it meant it would excuse her....."you know Danny, he's married, he tries out all the girls and gives them instructions how to fuck the customer and what positions to use. It didn't mean anything, it was like a job interview. I hadn't decided I want to be a working girl but he offered a $100 bonus."

"At first he just asked to have me naked, to see what my value would be. Then he pulled his pants down and asked me to suck him a few times so he could see how much I can take. I think he even came a bit in my mouth. By then I was lost in what to do as I was naked, he is my boss and I'd already taken the money.  He was saying such nice things about my body I got lost in where I was and forgot all about you.  Finally he told me to kneel on the bed so he could check my pussy. He said he has very particular clients and he has to know the girls well so he can match them to clients needs."

"So I bent over on the bed thinking he would maybe look at my pussy up close. I rested my head on the bed, it was spinning realizing that I had just sucked my bosses dick, even if only a few strokes.  All of a sudden I felt a force on my pussy.  It took me by surprise.  As I was now being rocked forward I realized he had plunged his cock into my pussy and was fucking me. I was helpless as my arms were rest backwards so I couldn't move away with him pushing me forward with his pelvis.  He must have been fucking me for a minute before I turned my head to the mirror along the bedside. I could see this middle aged, slightly overweight man having sex with a 24 year old taunt body.

I was frozen at the sight, maybe a bit turned on, as I've only ever been with athletic slim younger guys like you." 
"Danny!  Danny! I finally yelled to him", "have you seen enough yet? I wasn't expecting this, my boyfriend will be mad".

She looked me in the eyes at that point, before continuing,
"Danny then pulled back, saying he was finished anyway. I looked at the side mirror back at him, his cock looked like it was dripping, but he quickly put it back in his pants. I never even saw if he put a condom on.  We went back out to his office and he said he would show me the rates he could pay if I went full-time with clients."

"He looked down at his laptop closely then punched some numbers to his calculator, turned and showed me.  It was more than 5 times what you make baby..." she said proudly at me. "Danny says I could be a top tier girl for premium clients".

By this time I was furious. "I don't give a fuck about the money, you just had sex with your boss and are now talking about getting paid for sex everyday".  She got a smile on her face and replied "but you know I love sex, the money is unbelievable and I'll always save the best stuff for you!"

At that time she grabbed my crotch, and started unbuckling my jeans.  "Honey, I know Danny is kind of old, but I got so horny when he was inside me, maybe I want to experiment more with older guys."

She put my now firm cock in her mouth and sucked.  My mind could now only think I wanted to fuck this slut in front of me immediately.  I reach down to her skirt, unzipping and sliding off in one motion. I reach to her panties, which had a damp spot from her earlier try-out. It crossed my mind that I just touched Danny's cum which had trickled out of Amy's pussy.

I pulled my cock away from her mouth and with my hands on her waist, moved her onto her knees.  Moving behind her I slid my stiff cock into her wet pussy.

Amy got excited, "oh yes, I need more cock, Danny fucked me good but I just wanted him to keep going today. After he finished I was ready to take the next guy through the door, it was such a turn-on!"

I kneeled over, banging her from behind, knowing it was the same feeling she got from Danny. His cock leaving her a treat behind that my dick was sliding against. I moved faster, wondering whether I was actually turned on by the thought that she wanted to spend her days fucking strangers.

It felt like the best sex we'd had together right through to the finale as I released my hot cum into her pussy, a spot which in the future which could well become any man's.