Step-sister's demonstration

Hello dear - welcome home! I thought I'd drop by to say hello to my step-brother and his girlfriend, but I didn't realise you'd be working so late.
Sindy here tells me you've never said anything about how I used to keep you in line at home. I'm shocked! Why wouldn't you tell her how I used to discipline you when you were rude or naughty?
So we've struck a deal. She's chosen your outfit, which you'll find in the bathroom. I want you to go and get changed.
My side of the bargain? I'll show her exactly what naughty boy-girls get, dressed in their stockings, girdle, knickers and bra.
And I have everything I need right here in my bag. The furry black cuffs. Your favourite vibrating nipple clamps. The feather I need to tease you to stiffness.
Oh, and of course I brought two strapon cocks - it wouldn't be fair for your step-sister to hog all the fun without letting your girlfriend feel how tight your arse is, now would it?
Go get changed, sissy boy.