Play word 切腹 切腹 せっぷく seppuku as a death penalty (where the convict is decapitated by a second as they make the motions to disembowel themself; Edo period)
Play word 陰腹 陰腹 かげばら secretly slitting one's belly (and only eventually revealing one's mortal wound) (in kabuki, bunraku, etc.)
Play word 思う事言わねば腹膨る 思う事言わねば腹膨る おもうこといわねばはらふくる if you don't speak your mind, you'll feel uneasy afterwards