Can't get it in

Hi there, I'm new to anal play and I have an aneros MGX for starters. I love when my girlfriend delivers some anal play for me so I decided to try the aneros. I've tried for the last two nights to just get the thing into my anus, but I can't seem to get it to the prostate. I have some of the glide lube stuff and I put the aneros in warm, soapy water before use but I just cannot get it.

I have tried every position I can think of to get this thing in. The closest I've gotten is laying on my side, putting both my knees at about a perpendicular angle to the rest of my body and slowly insert, but I still haven't gotten it all the way in yet. When I get to a certain point it just doesn't seem to go and I don't want to force it as I am afraid it may hurt something in there.

Just from what I've been able to do so far, I have noticed way stronger and better orgasms. I can only imagine how it will feel once it's all the way in.

Does anybody have any recommendations or tips for a newb? Thanks a lot!