To answer a couple of questions, yes the girls will participate if tipped well and they know you are not a cop.
Man, one of these shops was the scene of one of the top ten hottest things that I have ever experienced. To put this in perspective you first have to know that my wife an I are very open and have a zero jelousy factor when it comes to each other being with other people. So, please don't freak when you read this and think i am cheating.
Shortly after we were married in 1990, her sister had come over to our house to show off her new boob job. She looked really good at the time - about a 19" waist and the new 32 D's put her over the top. She and my wife were having some wine when I came home and she took her top off on the sofa and let me really check 'em out. Okay, so they were pretty tipsy and my wife and here were talking about her job and that she was starting back. Talking with them I found out that her sister worked at one of these lingere modeling places and they were really cracking up and goofing about some of the weirder dudes who would come in.
That said, I only waited a week to go to the shop that she worked at. It was too cool when I walked in and there she was with about three or four other fine ass chicks dressed in different lingerie watching tv. Maybe three chicks and my sister in-law sttod up and smiled and one walked up to me and asked if I wanted a session and told me the price. Man, I was buzzing with anticipation and asked if I could pick any girl or if I had to take her. She said I could have my pick so I , of course, ponted out my sister in-law who had not said a thing, but was smilling and had whispered to on of the other girls I guess that I was her brother in-law cuase she let out a little laugh and smilled bigger. Man, I was about to bust one right there when she took my hand and let me back to a room and asked if here sister put me up to it. She asked if I knew the 'drill' and then winked or somethin and told me she'd be back and if i wanted to i could get comfortable as i liked. So, when she left I stripped!!
When she came back she said something like "oh, shit" when she saw me naked and was having a hard time composing herslef kinda laughing and saying she didn't know if she could do this with a straight face. She turned on the tape deck and started some very fine slow dancing for me. She took her bra off and came over to me while i was playin' with 'it'. She asked if I was gonna tip her and I gave her about $50.00 bucks and she took off her thong and fuckin' grabbed my balls right there. Then she pulled out some lotion and jerked me off right there while I played with her ass and tits, It was awsome!! For other reasons my wife and her are not as close as they used to be, but she has come over a couple of times at Christmas and she makes little inside jokes about the heat and shit like "is this as comfortable as you like it in here". It's a hoot.