An apparatus is configured to apply an adjunct material to a stapling surface of a jaw of a surgical stapler. The jaw includes an outer surface disposed opposite the stapling surface. The apparatus includes a housing and an arm. The housing includes a first contact feature that is configured to contact one of the adjunct material or the outer surface of the jaw. The arm is operatively coupled with the housing. The arm includes a second contact feature that is configured to move relative to the first contact feature to contact the other of the adjunct material or the outer surface of the jaw. The first and second contact features are configured to cooperate to apply a compression force in a direction toward the first contact feature to pinch the adjunct material against the stapling surface to mount the adjunct material to the stapling surface.