With the rounded balls and lack of pointy areas this is actually a very comfortable, and highly unlikely to cause harm, toy. However, like others have said, ANY toy can cause harm if you aren't slow and careful especially in the beginning of the play session before you are really warmed up. The anal sphincters really have a mind of their own and some need a whole bunch of persuasion while others are raring to go from the beginning. Learn where you fall in the spectrum, grab some good quality lube and use plenty of it.

I would also suggest playing with the toy orally and vaginally at first so that you can see that it doesn't have sharp edges that could poke and tear sensitive anal tissues. It's completely non-porous so as long as you begin the session with oral/vaginal play and then move to anal there's no chance you'll cross contaminate! If you are REALLY worried you could try slipping a thin but large sized condom over the side you are playing with until you have a bit more confidence with the toy. less