"if it's yellow let it mellow" meaning in English

{
  "etymology_text": "A short version of \"if it's yellow let it mellow, if it's brown flush it down\".",
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "phrase"
      },
      "expansion": "if it's yellow let it mellow",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "phrase",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "2011, Kirsty McKay, Undead, →ISBN:",
          "text": "It's a tad gross that I haven't been able to flush, but if it's yellow, let it mellow ... and run like hell-o.",
          "type": "quote"
        },
        {
          "ref": "2013, Laura Portwood-Stacer, Lifestyle Politics and Radical Activism, →ISBN, page 29:",
          "text": "He went on to explain: I'm not gonna waste like a gallon and a half of water that we're stealing from the Colorado River just cuz I took a pee, you know like, 'if it's yellow let it mellow,' you know, don't flush it.",
          "type": "quote"
        },
        {
          "ref": "2016, Bo Bennett, Logically Fallacious, →ISBN:",
          "text": "Explanation: No! I did not have to follow the, “if it's yellow, let it mellow” rule—in fact, if I did follow that rule I would probably still be single.",
          "type": "quote"
        }
      ],
      "glosses": [
        "In order to save water, do not flush the toilet every time you urinate."
      ],
      "id": "en-if_it's_yellow_let_it_mellow-en-phrase-dx8zjcHa",
      "links": [
        [
          "save",
          "save"
        ],
        [
          "water",
          "water"
        ],
        [
          "flush",
          "flush"
        ],
        [
          "toilet",
          "toilet"
        ],
        [
          "urinate",
          "urinate"
        ]
      ]
    }
  ],
  "word": "if it's yellow let it mellow"
}

{
  "etymology_text": "A short version of \"if it's yellow let it mellow, if it's brown flush it down\".",
  "head_templates": [
    {
      "args": {
        "1": "en",
        "2": "phrase"
      },
      "expansion": "if it's yellow let it mellow",
      "name": "head"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "phrase",
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English phrases",
        "English terms with quotations",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "examples": [
        {
          "ref": "2011, Kirsty McKay, Undead, →ISBN:",
          "text": "It's a tad gross that I haven't been able to flush, but if it's yellow, let it mellow ... and run like hell-o.",
          "type": "quote"
        },
        {
          "ref": "2013, Laura Portwood-Stacer, Lifestyle Politics and Radical Activism, →ISBN, page 29:",
          "text": "He went on to explain: I'm not gonna waste like a gallon and a half of water that we're stealing from the Colorado River just cuz I took a pee, you know like, 'if it's yellow let it mellow,' you know, don't flush it.",
          "type": "quote"
        },
        {
          "ref": "2016, Bo Bennett, Logically Fallacious, →ISBN:",
          "text": "Explanation: No! I did not have to follow the, “if it's yellow, let it mellow” rule—in fact, if I did follow that rule I would probably still be single.",
          "type": "quote"
        }
      ],
      "glosses": [
        "In order to save water, do not flush the toilet every time you urinate."
      ],
      "links": [
        [
          "save",
          "save"
        ],
        [
          "water",
          "water"
        ],
        [
          "flush",
          "flush"
        ],
        [
          "toilet",
          "toilet"
        ],
        [
          "urinate",
          "urinate"
        ]
      ]
    }
  ],
  "word": "if it's yellow let it mellow"
}