My husband just tried it for the first time last night, but he wouldn’t let me watch because he’s embarrassed and said he won’t tell me what he thinks about it until he’s tried it a few times, so I’m patiently waiting 
I was also not sure how this toy would be combined with penetrative sex, also if the arms would get in the way or pinch anything. The product page says, “Enhance oral play by adding this booty beauty into the mix,” and the info on the user guide it comes with (and on the manufacturer/competitor’s site) to contract your sphincter muscles and do relaxation exercises when it’s in, so not sure if it was designed with penetrative sex in mind, so I’ll guess I’ll just wait and see what he wants to do after he gets used to it 
@hornycouplebythesea has this one too (Aneros Trident MGX Prostate Massager), and @Floating_Fun_Guy has (or had) the Aneros Progasm Jr. Prostate Massager (I saw his review on the shopping site) which also is supposed to be a beginner one but is a bit thicker, and they’ll definitely have more to say than me on this 
The Prostate Massager recommendations for first time user thread might be a good read if you haven’t already 