Ok, let me start off by saying that this is a very big toy.
It's not intended for someone who is new with anal play.
You need to have knowledge on how to use bigger anal toys too.
And have the correct lubes to use it with.

Even though this toy is waterproof, make sure you lube this toy up very good.
Also, because of exiting.

~ About the Toys material:
Its very big, like I said, but definitely doable for experienced users.
The toy is flexible, but has a strong tension and returns to its own shape (in terms of how strong the flex is).
The material is silicone and it's very soft. It does smell a bit funny though.
And it has a small line across its length, but it's not very rough, but you can feel it with your finger tips.

~ About the buzz:
I read other reviews about how amazing the buzz is, but I have to disagree completely on that one.
The buzz is very weak and doesn't go through the whole toy and stays in the base.
It's a small bullet, with a small button and gives a single high pitch buzz when pressed.

~ Insertion:
Inserting for me was a bit difficult; I had to use a lot of lube.
And you don't really feel the ball shapes of it, as it goes in.
Then it feels like you are there, but you are not, because there is still one really big ball left (Which I think is a bit overdone and hard to get in, due to angle.).

I really am not very excited about this toy, but perhaps it's just because I'm slim and it's a bit big.
I might get my hands on the smaller one and review that too.

I was most disappointed by the buzz and a little bit about the smell.

For me its a 2/5, because it you read a lot about how great it is, but it really isn't that great. (for me at least)

Remember that for others it can be experienced differently, but this is my personal honest opinion.