Two mares named Minty and Grapevine get drunk, dismantle a newsroom, and have a little "fun" with a bottle afterwards. Unrelated to Two Girls, One Cup.
Grapevine: Purple Mare
Minty: Blue Mare

A little scene based between Chapters 8 and 9 of ToixStory's Freeze Frame You do not need to read Freeze Frame, to know what is going on here