OK, I've had mine for about a week now and used it on three nights. Some observations, I bought the medium which seems about right. After some preparation, (nothing a average bottom wouldn't do anyway, it slipped right in with no issues. One thing I discovered, you can't walk around with it inserted, it will slip right out. (Or, I'm just to sloppy a bottom). You can't walk around a bath house with it in place, a negative for me.
In bed, it stayed in place and my top had no trouble getting in well lubed. He liked the ribs inside and felt stimulated. I had to reach down and push it home a couple times as it felt like it was slipping, but as my top pushed back in, it went in as well, too aggressive fucking, it will pop out. As a bottom, I think it takes away from the sensation of having a cock fucking you, and I lost a lot of feeling that I normally expect. Overall. not a bad toy for occasional fun, but not a regular play toy for me.
I voted "OK". Thanks Ft. Troff for the great service.