The 6-2-1 rule is a furry convention hygiene guideline. The rule mandates the following:

6 hours of sleep per night.
2 meals per day.
1 shower per day.

These numbers are lower limits and not intended as upper limits. The third part of the rule is to prevent con funk - all parts help to avoid con crud and concurrent post-con depression.
Source: 6-2-1 rule Wikifur
1: "Oh man, I'm so tired..."
2: "Well, did you stick to the Rule 621?"
by Samadadood July 10, 2018
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Rule 621 states that for every famous person there is at least one fursona based on them.

Rule 621 is named after the furry website e621.net and is a subrule of Rule 34.
Searching Carl Lancaster just beings up a bunch of rule 621 fanart
by The Eerie Red Light December 6, 2017
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If it has animals, there is furry porn of it. A subset of rule 34. Named for the furry imageboard e621.
"My niece couldn't spell Ratatouille so I Googled it for her, and we accidentally found Ratatouille porn. Why, internet, why?"
"Because rule 621."
by laofmoonster August 30, 2013
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