Deeper penetration? slightly nsfw.

So I finally came to terms with my sexuality a couple of years ago and actively started experimenting. I love the feeling of anal penetration and purchased a small dildo to start the fun but I have a problem. I cannot seem to go any deeper than a few inches! It is so frustrating because eventually I want to move up to larger sizes and be able to accept my partners easily. Do you have any tips or toys that could help me? Maybe I'm doing something wrong? Thanks :)