Haven't watched the video, but I followed most of the debacle. The guy isn't the most stable and it's not the first time he scams people with a fake product.
I did try to set a safe word prior to that incident but she laughed it off and said we didn't need one. Fortunately things never got really ugly, even if this is not the only crazy fantasy she pestered me with.
My ex pestered me for a good while with a fantasy: she wanted me to force her to have sex any day she didn't want to. I wasn't exactly eager to try this, but it wasn't a problem because we were having sex every day.
But the day came, and I said "well, she's been asking for a while, let's get this over with". She didn't need much convincing, I just grabbed her by the back of her neck and told her we were going to have sex no matter whether she wanted or not and that was it (she was quite submissive in bed).
After we were done I had a weird feeling because that's not something I like to do, but I thought "at least I've fulfilled her fantasy and now she's happy", right?
Well, no. She was angry at me and when I told her "but you've been asking for this for months!" she answered "yeah, but I wasn't in the mood for it today!".
Edit: This was supposed to be a gif I had in storage, but I suppose it's fossilized after all these years.