Originating in Glasgow, Scotland "night night patter" is when you get to that part of the night when everything that's not funny becomes hilarious, all whilst needing no explanation. Night night patter is usually paired with illegal substances such as acid, ketamine and alcohol.
Night night patter in itself cannot be fully defined, however here are some examples I have come across.
Person one - 'mate look at the state of her, she paints her fucking nails"
Or
Person one - "Know what I'd love? A nicevegansandwich and a bit of dick"
The act of smoking a pinch or two of typical good cunt aka maryjane from a bong. To tuck yourself into bed. A very pleasant experience, you will awake the next day feeling very refreshed.