Since this word has okurigana (hiragana attached to the kanji) you know that it's probably going to be the kun'yomi reading.
Lucky for you, the kanji readings for transitive and intransitive verbs are almost always the same. Once you learn one, you know them both! This reading is the same as 刺す.
Be careful to not get pricked by a thorn.
The arrow pierced my head.
Those words felt like a knife in my heart.