pin (someone or something) beneath (someone or something)
To restrain or immobilize someone or something beneath someone or something else. Often used in passive constructions. The earthquake pinned me beneath a fallen beam. He was pinned beneath the giant wrestler. I pinned the trap beneath a hefty boulder to keep it from being blown away.
pin someone or something beneath (someone, something or an animal)
to trap someone or something beneath someone, an animal, or something. The mine cave-in pinned four miners beneath a beam. I held the alligator's mouth closed and pinned it beneath me.