I will get a little comfortable on my coach, while you squrim like a worm on the floor.
Now, I want you to put a scissors on the floor in the next room and put your handcuff keys somewhere at the end of the room. So you can reach both of them. You already got some experience with squirming and humping, so those cuffs around your ankles, will remind you, where your place is.
Now pull the ziptie through the chain of the handcuffs on your ankles, but leave them open.
What... you are so horny now? I will allow you 20 more slow strokes... gather all that droll from your chin and use it, to cover your cock in it!
Now put that belt around your upperbody and slip your arms under. So that the belt goes around your body and your arms, above your elbows. Dont make it too tight... no need for that.
Feeling snug?