How often is too often?

I recently bought an Aneros Progasm having had no experience to prostate massagers before.

I tried it yesterday and again today. Felt really good, nothing mindblowing yet though.
I would want to use it again tonight, but having read all the recommendations to have a few days between sessions, I’m wondering are there any risks to it?
I don’t mind if I don’t get to experience a super-O yet, I just really don’t want to break my ass.