drum
鞀 centers on a drum, specifically a small hand-held drum used in ancient contexts. The meaning is straightforward and tied to a percussion instrument.
鞀 combines 革 (leather) with 召, which likely contributes the sound. The character refers to a small drum, historically made with leather stretched over a frame.
The left side 革 means leather, and the right side 召 looks like a hand beating a drum. Picture a leather drum being struck to summon people.
For トウ, imagine a toe tapping on a small leather drum: toe -> トウ, and the drum beats out the rhythm.