The Tea analogy came from a blog post in 2015 and remains spot on in its description of consent. The message was so powerful that it was made into an animation and went viral.
The original post can be found on the following link. I feel it is good to credit the author rather than plagarise her work.
Thames Valley Police used it as part of a #consentiseverything campaign and it was published on metro.co.uk
The video is here
And the article is here