甜到發膩的感情
糖漿的甜是可以過量的：多了就黏牙、化不開。把這個口感搬到話語、音樂和電影上，就成了肉麻。
noun · C1
Words, music, films or gifts that show love and other warm feelings in a way that is far too sweet, so it feels silly, and often not quite honest.
肉麻煽情
核心畫面
One way to picture treacle: the thick syrup left in the pan after sugar has been boiled. It is dark, it shines, and it pours far more slowly than water. It is very sweet — sweet enough that a little is lovely and a lot is too much. Hold both halves of that picture, the slow stickiness and the too-muchness of the sweetness, and the other uses of the word follow from it.
可以想成煮糖之後留在鍋底的那一層濃漿：深色、發亮，倒出來比水慢得多。它很甜，甜到一點點很好、多一點就膩。把這個畫面的…更多收起
可以想成煮糖之後留在鍋底的那一層濃漿：深色、發亮，倒出來比水慢得多。它很甜，甜到一點點很好、多一點就膩。把這個畫面的兩半都記住——又黏又慢，以及甜得可以過量——這個字後面的用法大致都從這裡長出來。From the word’s history
Wiktionary traces treacle back through Middle English triacle to Ancient Greek thēriakḗ, 'an antidote'. The medieval antidote was a sweet, thick paste taken by the spoon, and the word followed that texture into the sugar pan.
依 Wiktionary，treacle 一路上溯到古希臘文 thēriakḗ「解毒藥」。中世紀的解毒藥是又甜又稠、要用湯匙挖的膏狀物，這個字就跟著那個口感，最後落在煮糖剩下的濃漿上。
Wiktionary, entry 'treacle' (packet etymology_text; source_ref kaikki:3f6f69a190036ae4:670919099:17956)
From the picture
倫敦街頭的叫法
這一支不是從糖漿比喻過來的，走的是聲音的路：Cockney 押韻俚語 treacle tart 押 sweetheart，說久了只剩前半截。
noun · C2
Used in London street speech when talking to a woman, in the way that 'love' or 'sweetheart' is used. It comes from the rhyming slang 'treacle tart', which rhymes with 'sweetheart'.
親愛的（倫敦俚語）
Also in this word
noun · C1
A thick, dark brown or almost black liquid that is left when sugar is made from sugar cane. It is very sweet with a slightly bitter taste, and cooks use it in cakes, biscuits and puddings.
黑糖蜜
noun · C1
Golden syrup: a thick, clear, golden-coloured syrup made from sugar, very sweet and without the bitter taste of the dark kind. It is poured over puddings and used in baking.
金黃糖漿