How it began (2/x)

(Part 1: https://www.ashemaletube.com/story/how-it-began-1-x-6645/)

...
I felt more and more anxious and nervous the longer I was alone in that bed, unable to move, unable to see what was going on and unable to do anything but wait. After maybe an hour - it might have been less or might have been more - the door opened again and my girlfriend entered.
"Hi hun!" she said, "I've been successful and found someone to join us tonight. Do you remember the video I showed you lat night?"
"Yes, of course", I replied and felt my cock twitching a little in excitement. It was a porn clip with two girls and one guy with lots of anal, ass-to-mouth, cum-swapping and swallowing. "Is she already here?" I asked.
"No, not yet. Our playmate will arrive soon, but I had to promise to make some more preparations. It's kinda kinky, but you'll love it, so keep still and we'll soon have our first threesome, ok?"
"Alright", I replied.
She told me to open my mouth and within a second I had a ball gag in my mouth and fastened behind my head. "Don't worry, hun. I will tell you what's going on, you don't have to ask. First of all, I'll give you something nice to wear."
I could feel some satiny fabric on my feet and she pulled them up. The fabric felt tight around my legs. "Some nice lacy black hold-ups for you." I felt excited, but also embarrassed thinking about another woman that would come in and see me like this. A few moments later I was wearing a black string and I had two clamps with a small chain attached to my nipples.
She tied ropes to my ankle and tied the ends to the bedposts above my head, so my butt was exposed.
My excitement grew with my anxiety that soon I'd be exposed and humiliated in front of an unknown woman.
"That looks great, hun. Just some more small details." Before she had finished that sentence, I felt a well lubed small plug being pushed in my ass. Next, she pulled the string aside and carefully trimmed my balls and asshole, which made my cock grow to full size, making it difficult for her to put it back into the string.