firewood for sacrifice
槱 centers on wood used as fuel for a ritual fire: firewood specifically gathered for a sacrificial burning.
槱 combines 木 (tree, wood) with 酉 (a wine vessel) and 灬 (fire). The character likely depicts wood being used in a fire ritual involving wine, but the exact historical development is uncertain.
A wooden 木 wine vessel 酉 is placed over a fire 灬: imagine sacred firewood being burned as an offering.
For ユウ, picture a ewe (a female sheep) being led to a sacrificial fire: ewe -> ユウ, and the firewood is ready for the ritual.