*tight as a tick
1. very tight. (Fig. on the image of a tick swollen tight with blood or of a tick stuck tightly in someone's skin. *Also: as ~.) This lid is screwed on tight as a tick. The windows were closed—tight as a tick—to keep the cold out.
2. intoxicated. (Fig. on full as a tick. *Also: as ~.) The old man was tight as a tick but still lucid. The host got tight as a tick and fell in the pool.
3. [of a race] close, as if the racers are moving very closely together. (*Also: as ~.) This election is as tight as a tick.
4. very friendly and close; as thick as thieves. (*Also: as ~.) Those two are tight as a tick. They are always together.