He has no idea why you can't get a girlfriend of your own. All those double-dates we invite you out on and you always go home alone. I've found so many pretty girls for you but none of them ever work out - if you're not careful your best friend is gonna think you're gay! Maybe we should just tell him the truth huh? Maybe we should tell him that his girlfriend has you locked in chastity - so there's no point trying to get you laid. Your best friend's girlfriend has you all locked up in chastity - maybe we really should let him in on the secret huh? And then maybe we should tell him EVERYTHING! How I make you wear panties - MY panties. How I've been blackmailing you, how I dominate and humiliate you? Should we tell him or keep it our secret?
How does it feel when I invite one of my hot girlfriends to double date you with us? Does your little pink cock-cage hurt when she's flirting with you? Y'know all my girlfriends know about it right? All the dates I bring along for you know you're my secret slave - locked in chastity, butt-plugged and wearing my panties. They all know - that's why they wear the hottest outfits, the shortest skirts, the tightest tops - that's why they flirt with you SO much! They're doing it to torture you! They're doing it to make you suffer in that chastity cage. They're doing it because they all know there's not a single thing you can do about it!
I've loved fucking with my boyfriend's best friend so much but best of all - I've loved blackmailing you. You know just how much trouble you'd be in if he ever found out about you don'tcha? If he knew you served and worshipped his girlfriend like an obsessed puppy - he'd be so angry! If he ever found out that you wear my panties - that you've allowed me to snap you into a chastity device - that you do everything I tell you... he'd totally flip-out! Which is why you're gonna keep paying me to keep my pretty mouth shut and you'll keep doing as you're told. You're gonna keep getting teased and blue-balled on dates by my mean-girl girlfriends and you'll keep that little dick limp and lonely in it's chastity cage because when it all comes down to it - you don't have any choice fucktard!