Instant involuntaries?

First off I do not have aneros product but something similar, and seeing as this subreddit it is active I thought this would be the best place to ask. I have done a few sessions and each one gets better and better, but last night was weird as soon as I got relaxed with the toy in, my legs and body started shaking, almost shivering like I was cold but I wasn’t cold. Is this what involuntaries are? I haven’t had any of the shaking in any previous sessions and find it weird that it started almost as soon as I put it in. The shaking got a bit more intense but after awhile I moved and they stopped coming so I got impatient and ended up climax the normal way.

Also I have heard that vibrating products are a bit overkill is this true? The one I have does vibrate but I did not have it on vibrate at first to get comfortable with it in.