Green’s Dictionary of Slang

1. (US black) a drum or drum kit.

1938		Eve. Sun (Baltimore, MD) 19 Dec. 21/4: Suitcase: drum.
1939		P.E. Miller Down Beat’s Yearbook of Swing n.p.: suitcase : drums.

2. (US) the anus.

1992

Bentley & Corbett Prison Sl. 62: The Suitcase The anus.

3. see Brixton suitcase n.