pin (someone or something) against (someone or something)
To shove someone or something up against someone or something else and forcefully hold them or it in place. The car slammed into the man and pinned him against the tree. Pin the tarpaulin against the ground while I nail it down. The bully pinned me against his friend, demanding I give him my lunch money.
pin someone or something against something
to press and hold someone or something against something. The police pinned the mugger against the wall and put handcuffs on him. The wildlife veterinarian pinned the rhino against the walls of the enclosure and subdued it so it could be treated.