Fuck your wife right before you go see her best friend. When she starts sucking you tell her to tell you how she likes the taste. When she moans. Tell her she is tasting her best friends pussy juices as you pump her mouth pinching her nipples. and you cum in her mouth. Tell her you would love to see her seduce your wife so you can walk in on them and join in. No more hiding. Mmm now you can have three somes with your wife. Maybe her best friend can get her wilder than she ever been.
Not a bad setup, but I'd be careful. I used to fuck one of my wife's friends, lasted for about a year before she confessed to my wife what we had been doing. Then again, if you've been getting away with it for 5 years, maybe you're in the clear.