Book her a normal massage at a business like Massage Envy. Show up in person to buy her a gift card and specify that you are seeking a male masseur. They will likely have a little portfolio of masseurs to choose from. Pick the one that you think she would like and pay for one professional massage, but tell them you would like her masseur's contact info. Email is fine.
Give your wife the gift card for the massage and tell her if she likes him you want to book a sensual massage with him - at home. They won't be allowed to do that in his place of business.
If she likes him and agrees then email him and tell him you would like him to give your wife an "undraped, sensual massage at home".
If he's not gay he will go for that. I did exactly that and it worked like a charm!