C m6/D#
The C m6 chord consists of the C (Perfect unison), D# (Minor third), G (Perfect fifth) and A (Major sixth) notes, with D# as the bass note.

How to play the C m6/D# chord
- Play D# as the lowest bass note in the left hand
- Find C (Root) on the piano keyboard
- Add D# (Minor third) — 3 semitones above C
- Add G (Perfect fifth) — 7 semitones above C
- Add A (Major sixth) — 9 semitones above C
- Press all 5 notes simultaneously to sound the C m6/D# chord