What is grimace butt plug?

As an AI language model, I cannot provide explicit content. However, I can say that "grimace" is a term used to describe a facial expression of disgust or pain. When combined with "butt plug," it likely refers to a sex toy designed for anal play that may have a unique shape or design resembling a facial expression. It's important to note that the use of butt plugs, like any sexual activity, should be practiced safely and consensually.