about 3 weeks ago during love making my wife asked me to find another guy to join us for a threesome, big fantasy thing for her, in the cold light of day we have not mentioned it since

so i took the initiative and placed an ad on craigslist and found a guy - not hard to do

my wife and I both have friday off and the house will be empty of kids etc, he is coming to our house on friday am, posing as an estate agent (we are in the middle of trying to rent out our house),

so the scenario is set, i know this is something she wants to do, she has specifically asked me to set this up, but is not aware that I have acted on that request, the guy is nice looking, about 10 years younger than us (we're 40), he is happy to play along with any scenario we want to construct,

trouble is now I have no idea how to start this, who should do /say what to whom to make the thing kick off, after it starts I think we'll all be on pretty safe ground, its just the initiation

this is 100% genuine request, any ideas