full as a tick

full as a tick {infml} (very full of food or drink; replete after eating or very drunk) — наесться до отвала; наесться так, что уже не лезет; объесться, упиться
also tight as a tick

Example 1: Little Billy ate and ate until he was as full as a tick. (CIDI)

Example 2: Our cat drank the cream until he became full as a tick. (CIDI)

Example 2: I’ve never risen from the table after a feed anything less than full as a tick. (OALD)

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A tick is a parasitic arachnid which attaches itself to the skin of a terrestrial vertebrate from which it sucks blood, leaving the host when sated (клещ). Alludes to a tick that has filled itself full of blood.

Related vocabulary
[eat one's fill]
[have a hollow leg]
[stuff one's face]
[pig out]
[I'm stuffed]