つっこんだ

put into, shoved into, got involved in

→ 突っ込む
つっこん rush into, charge into, plunge into + だ Past tense
verb · informal, past tense Rare #40,204
put into, shoved into
JA: 彼は鍵をポケットにつっこんだ。
EN: He shoved the key into his pocket.
got involved in
JA: 彼はその問題に首をつっこんだ。
EN: He got involved in that problem.
Conjugation of 突っ込む
Indicative past
つっこんだ

彼は本を鞄につっこんだ。

He shoved the book into his bag.

ベンは両手をポケットへつっこんだ。

Ben shoved both hands into his pockets.

パットったら厄介事に首つっこんだのよ

Pat went and stuck their nose into trouble.

— サスペリア (1977)