Keiko took the words to heart, making sure to remember that drinking alcohol was strictly done through the mouth. To really cement this lesson, she responded in kind."Gotcha, don't drink through your nose, lol."
What "lol" meant was alien to Keiko, but obviously Kokoro wouldn't have said it unless it was relevant. The girl wasn't much of an instant-messenger, preferring to have her conversations physically and face to face.
Speaking of her face, Keiko wore an expression of satisfaction, like all was right and balanced with the world, when Kokoro motioned to bite the handkerchief. Yet, the greedy gal decided to get more than her share! The protocol here was to return the action and bite the handkerchief, and the handkerchief alone--fingers were not a part of the transaction!"You can't just do that! That's not the law of equivalent exchange! *HAMPF*"
True to her beliefs, Keiko grabbed Kokoro's hand and lightly bit her finger back. Though, in her lack of dexterity, it was like Keiko just put the finger all the way in her mouth, nibbling at its base; however, it was rude to leave the finger dirty. So, gracefully and politely, Keiko sucked at the finger while drawing it out of her mouth, making sure excessive saliva wasn't left behind or anything.