You are my wife's best friend, whom I've been secretly fucking for a while now. Today, though, my wife walks in and catches us having sex (with you fuckbest friend is actually turning her on... so she lays on the bed with us and starts rubbing her pussy to orgasm, while both of you talk dirty (her urging me to fuck you/etc, you enjoying my cock/taunting her about fucking her husband/etc).

After my wife cums, she begs to share my cock, which you allow. I start switching between fucking one or the other of you, making you taste each other's pussy juices on my cock whenever I pull out. You both go on talking very dirty while I fuck you, until you feel that I'm getting close...and you demand I cum inside you and impregnate you in front of my wife. After I do, my wife licks your pussy to taste my cum out of your hole.

I leave the dirty talk up to you--the filthier and naughtier, the better (just no bathroom references). Be as creative as you like. I'd prefer my wife act more submissive and that you act more dominant. Any names you use for yourselves are up to you, and if you'd prefer to be the wife in this scenario, that's fine too. I think 15 minutes should be good for this one, and I'd like you to use my name (Chris) throughout.