There are two things I tend to base my rating on for anything: how much I personally like it, and how successful it is at being what it aims to be. The latter tends to be almost as important to me as my personal feelings.
Sonia GO aims to be a small, short, and sweet game for both PCs and android phones where you can undress and fondle Sonia, from Pokemon. It's made in Unity, well animated, the voice acting is good and sexy for her spoken lines, and even if the voiced lines get repetitive, I think it's cool that you can just let it idle while doing something else and she'll try to put on a show to entice you.
It achieves what it set out to do. And personally, I really love it. Small filesize, well made, and actually competently made at that, it runs smoothly even on a less powerful android phone. So, 5/5, you did good Washa.