The Zeta Creations "Euro Ruff Stuff":
I had to use lube to get the knot in, and it took me several minutes thinking it wouldn't be possible. But it finally went in and it felt *great* when it did. I love the feeling with it inside. I'm typing this with it still inside - I haven't taken it out yet. I'll update when I do. (I'm a little afraid it will be even more difficult coming out.) But if this how a real knot feels (and it expands and contracts when already inside) I wouldn't have a problem with it at all.
I will say, however, that I will never order anything from the website again. I ordered it - and still had received nothing after over 2 months. I email and opened a "trouble ticket" - and didn't hear anything back for a week. It was only when I really complained, telling them to keep their money and that I'd never bother with them again, that it finally got shipped. All in all, just *terrible* service. Stay as far away from these guys as you can. If you want one of their products, order from a different vendor instead.
