to bale out, to decant liquids
挹 centers on transferring liquid from one container to another: bailing out or decanting. The core idea is controlled pouring or scooping by hand.
挹 combines 扌 (hand) with 邑, which likely contributes the sound. The hand radical suggests an action done by hand, consistent with bailing or decanting liquids.
The hand radical 扌 beside 邑: imagine a hand carefully tilting a vessel to decant liquid into another container.
For ユウ, picture you bailing water from a boat: you -> ユウ, and your hand does the bailing.