It depends on who will be using it for the njoy. It's a great product, but for a partner to use it, it can sometimes get a little uncomfortable because you don't understand how far or where the head of it is. I'd recommend you probably start out with a toy that isn't so well, metal first off. But the njoy is definitely a great second toy.

I recommend any of the starter plugs on here. They're small, not scary, and are pleasurable to an anal beginner.

As for advice? Use lots of lube. Make sure he's thoroughly aroused before you attempt it. Calm him down because it will be ten-times more painful if he's nervous about it. Slowly ease your fingers in first (if you're kinda squicky about that, put a condom on your fingers). Go in a little bit then let him tell you if he's ready for more. After he's receptive to two fingers at a time, then it's time for the toy.

After he's used the toy in multiple sessions, you're probably ready to upgrade to a better toy. I hope that helps.