E2-F#2. Christlieb, Don. Pictoral Fingerings for Bassoon. Published by author, 1966, p. 19. Timm, Everett LeRoy. The Woodwinds; Performance and Instructional Techniques. Boston: Allyn and Bacon, 1964, p. 171.

x x x | x x x F
           F#-tr
    D

"Prepare a wedge of wood, cork, plastic or cardboard":

x x x | x x x
         E-wedged F#-tr

Heckel-System (German) Bassoon Trills and Shakes by Note Names